On two conjectural congruences of Sun involving harmonic numbers.

We confirm two conjectural congruences of Sun in Sun (Int J Math 26(8):1550055, 2015): ∑ k = 1 (p - 1) / 2 4 k H 2 k - 1 k 2 2 k k ≡ 7 2 B p - 3 (mod p) <graphic href="13398_2023_1422_Article_Equ23.gif"></graphic> and ∑ k = 1 p - 1 2 k k k 4 k H 2 k ≡ 7 3 p B p - 3 (mod p 2) <graphic href="13398_2023_1422_Article_Equ24.gif"></graphic> for any prime p ≥ 5 , where H n is the n-th harmonic number and B n is the n-th Bernoulli number. [ABSTRACT FROM AUTHOR]