a(n) = 2*(3*n+1)*(9*n+8).

Terms

a(0) =16a(1) =136a(2) =364a(3) =700a(4) =1144a(5) =1696a(6) =2356a(7) =3124a(8) =4000a(9) =4984a(10) =6076a(11) =7276a(12) =8584a(13) =10000a(14) =11524a(15) =13156a(16) =14896a(17) =16744a(18) =18700a(19) =20764a(20) =22936a(21) =25216a(22) =27604a(23) =30100a(24) =32704a(25) =35416a(26) =38236a(27) =41164a(28) =44200a(29) =47344