a(n) = (10*n+3)*(10*n+17).

Terms

a(0) =51a(1) =351a(2) =851a(3) =1551a(4) =2451a(5) =3551a(6) =4851a(7) =6351a(8) =8051a(9) =9951a(10) =12051a(11) =14351a(12) =16851a(13) =19551a(14) =22451a(15) =25551a(16) =28851a(17) =32351a(18) =36051a(19) =39951a(20) =44051a(21) =48351a(22) =52851a(23) =57551a(24) =62451a(25) =67551a(26) =72851a(27) =78351a(28) =84051a(29) =89951