A gathering to mark Sadat's work

The funeral of President Sadat will underscore anew the effects of his peacemaking efforts -- drawing the largest gathering of Western leaders to the Middle East in years and pointing up a conspicuous absence of Arab leaders.

President Reagan will not attend, but is sending an unprecedented delegation of three former Presidents -- Jimmy Carter, Gerald Ford, and Richard Nixon -- to represent the United States.

Israeli Prime Minister Menachem Begin, Mr. Sadat's partner in the US-sponsored Camp David peace process, will be among the foreign guests. He created an extra security problem by insisting on walking while in Cairo because of the Jewish sabbath. His presence was expected to ensure that most Arab leaders would stay away. Only Sudanese President Nimeiri and Moroccan Prime Minister Maati Bouabid, both politically sympathetic to Sadat, had said they would attend the ceremony.

Other dignitaries expected at the Saturday morning services include Prince Charles of Britain; the British foreign secretary, Lord Carrington; Italian President Sandro Pertini and Foreign Minister Emilio Colombo; West German Foreign Minister Hans-Dietrich Genscher; French President Francois Mitterrand and Foreign Minister Claude Cheysson; Japanese Foreign Minister Sunao Sonoda; Moroccan Premier Al-Motei Bou Ebeid; Indonesian Religious Affairs Minister Alamsjah; Swiss Foreign Minister Pierre Aubert; European Parliament President Simone Veil; and Thai Deputy Prime Minister Serm Na Nakhon.

Secretary of State Alexander H. Haig Jr. will head the U.S. delegation, which also includes UN Ambassador Jeane Kirkpatrick, Defense Secretary Caspar Weinberger, former Secretary of State Henry Kissinger. Traveling with the US representatives aboard Air Force One will be Sam Brown, a South Carolina ninth-grader who was a pen pal of Sadat and visited Egypt at the leader's invitation in 1979.