(1/30)*(p(p+1)(2p+1)(3p^2+3p-1)) where p is prime.

Terms

a(0) =17a(1) =98a(2) =979a(3) =4676a(4) =39974a(5) =89271a(6) =327369a(7) =562666a(8) =1431244a(9) =4463999a(10) =6197520a(11) =14822755a(12) =24607093a(13) =31137590a(14) =48343448a(15) =87633963a(16) =149111998a(17) =175917839a(18) =280200834a(19) =373671012a(20) =428943109a(21) =635050664a(22) =811727882a(23) =1148417997