President Reagan is planning the nation's 50th inaugural ceremonies Jan. 21 with a "We the People" theme -- an event more subdued and less exclusive than his 1981 Hollywood-style extravaganza that saw Washington awash in mink and limousines.

While the trappings of wealth and power will not vanish, inaugural officials announced yesterday that this time, more events will be free and open to the public, with the $500-a-plate candlelight suppers of 1981 giving way to fireworks spectaculars and a "young Americans pageant" at the Jefferson Memorial.

However, the invitation-only balls and entertainment galas of this inauguration will be exclusive in another way.

The 50,000 coveted tickets to those events will be allocated to states based on the number of votes they delivered to Reagan in his 49-state landslide victory, inaugural officials said.

That means the host of the inauguration, the District of Columbia -- which along with Minnesota handed Reagan his only losses -- could end up out in the cold. "Poor little D.C.," said Ann Heuer, chairman of the District's Republican Party. "I don't want to say what we're getting, but let's just say we're the low man on the totem pole."

In their first announcement of a frenetic four-day schedule of events to begin Jan. 18, inaugural committee officials yesterday said the celebration would emphasize "the unity and strength President Reagan has returned to America.

"President Reagan won reelection with broad support from Americans of all backgrounds, and this Inaugural belongs to them," said Michael K. Deaver, a top White House aide and the inaugural committee's general chairman.

"We want participation to be as broad and as wide as the president's victory."

Officials also want to bring in the celebration at a cost under the record-breaking $16.3 million price tag of 1981. But they acknowledged yesterday that they may not be able to pull that off.

For the sixth time in history, the Jan. 20 inauguration day mandated by the Constitution falls on a Sunday. So Reagan, following in the footsteps of previous presidents, will be sworn in during a "very private, very personal" White House ceremony Sunday, and again in a public ceremony Monday Jan. 21, Deaver said.

That day, Reagan will take the oath of office on the west front of the Capitol, which looks out on the mall. Then he'll join congressional leaders for a luncheon inside the Capitol, and finally, view the traditional presidential parade as it wends it way down Pennsylvania Avenue to the White House. That night there will be eight black-tie inaugural balls, with a ninth for "young Americans" at the D.C. Armory.

For the parade, there will be fewer bleacher seats, which require tickets, lining the route this time, and more standing-room space for the public, according to inaugural committee spokesman Jim Lake. But getting near the platform where the president is sworn in is another story.

"You'll need a ticket to spit on the ground up there," said one congressional aide involved in planning that aspect of the events. "Even the squirrels will be ticketed."

The presidential committee's planning for the event began the day after the election. "Mike Deaver thought anything done prior to the election would have been arrogant on our part," said Ronald H. Walker, who as chairman of the inaugural committee will run its day-to-day operations.

But several months ago the Armed Forces Inaugural Committee (AFIC), which provides support services to the Presidential Inaugural Committee (PIC), was already at work whittling away at a mountain of detail. AFIC, for instance, has gathered the necessities for the parade route: 120 "portopotties" or portable bathrooms, 1,534 tent stakes to erect 58 warming tents, 500 signs to tell marchers where they should be and 250 snow shovels everyone prays won't be needed.

Before the event is over, the AFIC staff will grow to 330 to support the PIC's staff of 156 paid workers and 400 volunteers. The D.C. government will have at least seven agencies on the job, providing everything from police traffic control to what one official promises will be the inspection of "every hotel, restaurant and hotdog vendor" in the city.

The security precautions alone involve the FBI, the Secret Service and the entire D.C. Police Department, working around-the-clock for the weekend. "Our strength is 3,880," said D.C. Deputy Chief John Connor. "And though they won't all be working at the time of the swearing in, everybody will be working that weekend to free the bulk of the force for the inaugural events," said Deputy Chief John Connor.

On top of the inaugural budget, funded by private contributions and the sale of official memorabilia and event tickets, the District has allocated $2.3 million for its role in the inauguration. The AFIC operating budget is $982,000, not counting salaries for personnel who are paid by the Defense Department, a spokesman said.

Similar government expenses drew fire in 1981 from Sen. William Proxmire (D-Wis.), who last week said, "It's inauguration time again . . . and the American taxpayers are going to be taken for an expensive ride."

Indeed, Deaver was asked whether there was any "discomfort" in holding an expensive gala at a time of huge budget deficits and large budget cuts. "This is a time for . . . Americans to celebrate and we have to go on and face the problems regardless of that," he said. "But I think it's a nice time to take four days out to think about the country and what we've got here."

Those four days will begin Jan. 18, with a free entertainment pageant on the White House ellipse, ending with a fireworks salute. That night, 12,000 guests, who will pay from $75 to $150 per ticket, will attend the first of two entertainment galas at the D.C. Convention Center. Singer Frank Sinatra is coordinating that event, as well as a Saturday night gala that will be televised by ABC, according to Deaver.

The committee hopes to raise a good portion of its funds by selling commercial time for that 90-minute show, whose stars were not announced yesterday. "We've got the president of the United States a second term and Frank Sinatra," said former White House aide Joseph Canzeri, who is planning the event. "That's not a bad start."

The rest of the weekend schedule is dotted with young people's pageants, leadership forums and concerts -- the president's nod to young voters for their support in his reelection. That support, said Deaver, "pleased Reagan more than anything else."

On Jan. 20, which also happens to be Super Bowl Sunday, the president will attend an invitation-only prayer service at the National Cathedral, before taking the oath of office at the White House. "There won't be much activity after 7 p.m., except in front of large-screen TVs," said Walker. "I know that's where I'll be."

This inauguration, Walker vowed, would be "run like a business" with line item budgets and the intent "to pay for everything we are responsible for."

But an inauguration, in scope and sensitivity, is like no other business. "You're dealing with the top brass of the entire country," according to one congressional aide who helped plan the last inauguration. "It's pretty hard to trump a senator," he added. "But here you have presidents and presidents' daughters. Usually the stakes aren't quite that high."

And no matter how well-laid the plans, something can -- and usually does -- go awry. Take, for instance, the carefully crafted seating plan for the platform where the president takes his oath -- seats that go only to cabinet members, U.S. Supreme Court justices, members of Congress and the presidential family.

In 1981, shortly before Reagan was sworn in, Frank Sinatra, who was not assigned to any of those seats, bluffed his way past several security checkpoints and seated himself there anyway, according to Tom Decker, then director of the special congressional committee that plans the ceremony. "What security guard was going to stop him?" Decker joked.

Another honored guest didn't approve of the platform seating arrangement and moved a few place cards around so things were more to his liking. "Suddenly everyone walked out," another congressional aide recalled, "and nothing was the way it was supposed to be."

But inauguration planners have survived such minor catastrophes in the past and do their best to prevent them in the future.

Yesterday, for instance, Deaver was asked whether before the inauguration the president and his son, Michael, would patch up family differences that emerged in press accounts last week. "Are there plans," someone asked "for a happy ending?"

"Plans?" Deaver repeated. "I wouldn't touch that one with a 10-foot pole."