(-1)^((p-1)/2)*Binomial(p-1,(p-1)/2) mod p^3 where p is the n-th prime.

Terms

a(0) =25a(1) =6a(2) =323a(3) =1079a(4) =924a(5) =3044a(6) =6252a(7) =254a(8) =21084a(9) =4217a(10) =42514a(11) =48955a(12) =63168a(13) =101333a(14) =90896a(15) =87970a(16) =164396a(17) =100099a(18) =85982a(19) =221337a(20) =464837a(21) =90637a(22) =214936a(23) =735552a(24) =171600a(25) =330425a(26) =437835a(27) =311632a(28) =363522