a(n) = n*(7*n-2).

Terms

a(0) =0a(1) =5a(2) =24a(3) =57a(4) =104a(5) =165a(6) =240a(7) =329a(8) =432a(9) =549a(10) =680a(11) =825a(12) =984a(13) =1157a(14) =1344a(15) =1545a(16) =1760a(17) =1989a(18) =2232a(19) =2489a(20) =2760a(21) =3045a(22) =3344a(23) =3657a(24) =3984a(25) =4325a(26) =4680a(27) =5049a(28) =5432a(29) =5829