a(n) = n*(8*n+1).

Terms

a(0) =0a(1) =9a(2) =34a(3) =75a(4) =132a(5) =205a(6) =294a(7) =399a(8) =520a(9) =657a(10) =810a(11) =979a(12) =1164a(13) =1365a(14) =1582a(15) =1815a(16) =2064a(17) =2329a(18) =2610a(19) =2907a(20) =3220a(21) =3549a(22) =3894a(23) =4255a(24) =4632a(25) =5025a(26) =5434a(27) =5859a(28) =6300a(29) =6757