The games of oil-price leapfrog being played by the Orgainzation of Petroleum Exporting Countries likely will add at least 1.5 percentage points to the U.S. inflation rate this year, according to several prominent economists.

That dose of extra inflation will, in turn, deepen the recession many forecasters believe is already on the way. If actual shortages of gasoline persist until next year, yet another full percentage point could be tacked on to consumer prices and unemployment fall an added half-point, one said.

Cargoes of oil now leaving ports in the Persian Gulf and Africa will cost, on average about $19 a barrel once transportation is included, and there is apt to be another leap or two within the next month.

Higher oil prices can have a depressing effect on the economy, whether the revenues go to U.S.. or OPEC producers, since oil users have less money left with which to buy other goods and services once their oil bill is paid.

Because of this, a panel of four well-known economists, speaking at a meeting here of the International Association oif Energy Economists, appealed to the Carter administration, Congress and the Federal Reserve Board not to tighten either monetary or fiscal policy any further.

"I would hope economic policy will recognize the depressing effects" of higher oill prices, said George Perry, of the Brookings Institution, one of the four.

"In round numbers," Perry said, "if OPEC prices go up $7 in 1979, that will add at least 1.5 percent to the Consumer Price Index . . . That only adds to the depth of the recession that was coming in any case."

Perry was focusing on the direct price impact. Otto Eckstein, who heads Data Resources, the economic consulting firm, also pointed to the potential direct effects of the gasoline shortage.

"If we don't solve the gasoline problem . . . in the next few months, we are going to make the recession worse, with unemployment down about one-half a point and inflation up by about a full point," Eckstein warned.

At $19 barrel including transportation, the cost of imported oil to U.S. refiners is up about $4.50 a barrel since last December - with no end to the increases in sight.

That $19 compares with sales of some more desireable types of crude oil at prices $2 and $3 a barrel higher.

About one-fourth of the country's imported oil comes from Saudi Arabia, whose basic price is only up 14 percent from last December instead of the 30 percent 40 percent for some producers

However, an attempt will be made at an OPEC meeting June 26 to rel-establish a single base price for crude. At that prting, the Saudis are expected to raise their price by at least $2.45 a barrel to $17.

That step alone would push the average cost of imported oil, landed in the U.S., to nearly $20 a barrel, with no assurances that still other hikes will not occur.

Alan Greenspan, the former chairman of the Council of Economic Advisers, nevertheless believes the coming recession will be mild unless there is a further disruption of oil shipments from the Persian Gulf area.

The situation in Iran is "very fragile," Greenspan cautioned. "They will be lucky to keep production at 3 million barrels a day."

Every with the boost to inflation and the added depth to the recession, Greenspan declared, "In the short run, we are overplaying the shortage and in the long run underplaying the risks of supply."

Eckstein and Perry also think the recession still is apt ot be mild, but the fourth panelist, Harvard economist Dale Jorgenson, told the meeting at the Sheraton Park Hotel, "There is no way we can avoid a severe deflationary impact as bad as 1974-75."

Other analysts disagreed with Jorgenson's dire predictions for these reasons:

Even at $20 a barrel landed cost, the increase in prices since December is only about $5.50. That higher price will also be reflected in the cost of domestically produced crude oil whose price is not controlled. In all, the $5.50 will be added to just over 60 percent of the oil lused inthe U.S.

Price-controlled oil will be rising, too, but only 50 cents or so a barrel.

Overall, the average price of crude will go up about $4, while the average price, stated in terms of 1979 dollars, went up about $7.50 between mid-1973 and mid-1974.

Another adjustment has to be made, however, to compare economic impacts. The 1979 economy is about 75 percent larger, mostly because of inflation, than the 1973 economy. Once that is taken into account, the $4 is reduced to $2.25.