In a story in yesterday's editions, the name of Richard Clark, of Northwest Washington, was inadvertently omitted from a list of 15 persons who have obtained signature petitions to get their names on the ballot in the special City Council election scheduled July 19, Clark said he is an independent.

Former D.C. School Supt. Barbara A. Sizemore picked up petitions yesterday to place her name on the July 19 special election ballot as an independent candidate for the D.C. City Council.

Mrs. Sizemore, who was fired as school superintendent in October, 1975, following nearly a year of heated controversy, must obtain $3000 signatures on petitions to get on the ballot. She will have to get an average of about 200 a day to meet the May 20 Elections and Ethics for petitions to be filed.

Her possibly entry into the campaign increased the likelihood of a lively race to complete the remaining two years of the term of Julius Hobson Sr. (Statehood-at large), who died March 23.

Hilda Mason has been chosen by the Statehood Party central committee to fill Hobson's seat until the election, and as the party's endorsed candidate in the race. Mason is a former school board member who was one of the most outspoken opponents of Mrs. Sizemore during the battle over her stewardship in the top school post.

The two are among 14 persons who have picked up petitions to run as candidates in the special election. So far only one of those persons, Naomi T. VanderJagt of Northeast Washington, has filed completed petitions. She plans to run as a Statehood Party candidate.

Many political observers were surprised by Sizemore's action, and early assessments of what her possible candidacy would mean were hard to come by.

Until Sizemore entered the race, Mason was considered the most viable candidate, with significant support being expected for two other possible candidates - Paul Hays, the Republican-endorsed candidate, and Susan B. Truitt, a former television reporter and once press aide to former Human Resources Director Joseph P. Yeldell, who hopes to run as an independent.

Sizemore is believed to have significant backing in many parts of the city, but she would be in her first city-Wild race.

City law permits only Republicans, Statehood candidates and independents to run for the vacancy because no party may hold more than two of the four at-large seats on the Council. Democrats already hold two.

In addition to Truitt, Mason, Sizemore, Hays and VanderJagt, those who have picked up petitions according to city records, include prison activist Ellwood Yango Sawyer (independent), former school board candidate Frank E. Sewell Jr. (independent), David von Sother (Republican) of Northwest Washington and James Clark, also of Northwest Washington.

Also, Leo A. Murray (Statehood) of Northwest Washington, Raymond V. Ellis (Statehood) of Southeast Washington, Bernice G. Hancock (Statehood) of Northwest Washington, Wane Jefferson (independent) of Northeast Washington, and Jackson Champion (Republican) of Southwest Washington.

Three-thousand names are needed to get on the ballot as an independent, and signatures of 1 per cent of the number of registered party voters are needed to qualify as a party candidate. For Republicans, that means 288,000 signatures, and for the Statehood party, 19 signatures.