When President Sekou Toure of Guinea entered the Madison Hotel last night, the plans for a receiving line went out the window. He was immediately thrust into a circle of embullient greeters. Beaming a wide smile at the response, Toure first bowed to HEW Secretary Patricia Roberts Harris and then embraced French Ambassador Francois de Laboulaye.

The informality, and Toure's obvious enjoyment as he talked effusively with 300 guests, indicated further that the African leader was anxious to present an upbeat view of Guinea. In the last four years, Toure, who has been a head of state longer than any other African leader, has gradually ended a long period of isolation. He has resumed relations with France, the old colonial ruler, and Ivory Coast and Senegal.

During the 17 years Toure has been president, he was pictured as a harsh ruler who put his strong view of African individuality above alliances that would help his extremely impoverished country. Now he is working hard to alter that view. "He is reestablishing himself as a world leader," said William Harrop, the deputy assistant secretary of State for African affairs. "We feel the human rights situation in Guinea has improved. The atmosphere is much better."

Standing with his ambassador to the States and one military aide, Toure characterized his meetings with President Carter and Secretary of State Cyrus Vance as a "reciprocity of willingness." Speaking through the ambassador, Toure said he noticed "a deep change in many characteristics of the country. The ascension of black Americans to high posts, has contributed to the social change and harmony. It's a test of justice here."

With his wife, Andree Toure, seated on a chair behind him, President Toure held his receiving circle for an hour. Ambassador Pierre Toura-Gaba of Chad was asked about his family and a Saudi Arabian journalist was hugged, as was the president of a mining company. "We have a rather large investment in Guinea - the largest bauxite mine in the world," explained Pedro-Pablo Kuczynski. "The improved political situation will only help the country's economy."

Before security cleared the hotel lobby, about 60 people had gathered to wait for Toure. Jan Bailey, a member of Mayor Marion Barry's minority business commission, had dressed in white as Toure had requested. "Most of the black Americans here have been admirers of President Toure for years, basically because he's a humanist at heart," she said. "His words today about there should not be any black races or white races supports that."

Ambassador Andre Coulbary of Senegal, one of several African ambassadors present along with envoys from Morocco and Jamaica, cast a friendly eye over the proceedings. "In the evolution of nations, there are moments of misunderstanding. I'm glad the African tradition of keeping the doors ajar was practiced by Guinea and Senegal," said Coulbary, referring to the two countries' past problems. "Toure's stature now is that of an elder statesman. His wisdom properly serves the African continent at this juncture." CAPTION: Picture, Patricia Roberts Harris, President Sekou Toure and Andree Toure; by Fred Sweets - The Washington Post