a(n) = (prime(n)-1)*(prime(n)-5)/12.

Terms

a(0) =0a(1) =1a(2) =5a(3) =8a(4) =16a(5) =21a(6) =33a(7) =56a(8) =65a(9) =96a(10) =120a(11) =133a(12) =161a(13) =208a(14) =261a(15) =280a(16) =341a(17) =385a(18) =408a(19) =481a(20) =533a(21) =616a(22) =736a(23) =800a(24) =833a(25) =901a(26) =936a(27) =1008a(28) =1281a(29) =1365