p(p^2-p+1) as p runs through the primes.

Terms

a(0) =6a(1) =21a(2) =105a(3) =301a(4) =1221a(5) =2041a(6) =4641a(7) =6517a(8) =11661a(9) =23577a(10) =28861a(11) =49321a(12) =67281a(13) =77701a(14) =101661a(15) =146121a(16) =201957a(17) =223321a(18) =296341a(19) =352941a(20) =383761a(21) =486877a(22) =564981a(23) =697137a(24) =903361a(25) =1020201a(26) =1082221a(27) =1213701a(28) =1283257a(29) =1430241