Given series: H23J, K31M, N39P, Q43S
The logic followed here is,
For First letter: H + 3 = K, K + 3 = N, N + 3 = Q, Q + 3 = T
For Number: All are series of prime number 23, 29, 31, 37, and 41
For last Letter: J + 3 = M, M + 3 = P, P +3 = S, S + 3 = V
Hence, the next term will be T41V.