0000719220-99-000003 DEF 14A 1 19981231 19990317 S&T BANCORP INC 0000719220 6022 251434426 PA 1231 DEF 14A 34 000-12508 99566708 43 SOUTH NINTH ST P O BOX 190 INDIANA PA 15701 7244651466 800 PHILADELPHIA STREET INDIANA PA 15701 DEF 14A 1 000071922099000003-001-seq1-def-14a.txt 1998 PROXY