1.Department of Mathematics and Physics, Luoyang Institute of Science and Technology, Luoyang, Henan 471022, China;2.Department of Mathematics, Shanghai Normal University,Shanghai 200234, China;3.Department of Mathematics, Luoyang Normal College, Luoyang, Henan 471934, China
Abstract:Harmonic numbers Hk=/j(k=0,1,2,3…) play important roles in mathematics. Let p〉5be a prime. We establish the following congruences:5HH≡-Bp-3- ,5H≡-pBp-3-p+ ,where B0,B1,B2,… are Bernoulli numbers given byB0=1 and Bk=0 (n=1,2,3,…).