a(n) = n*(16*n^2 - 1).

Terms

a(0) =15a(1) =126a(2) =429a(3) =1020a(4) =1995a(5) =3450a(6) =5481a(7) =8184a(8) =11655a(9) =15990a(10) =21285a(11) =27636a(12) =35139a(13) =43890a(14) =53985a(15) =65520a(16) =78591a(17) =93294a(18) =109725a(19) =127980a(20) =148155a(21) =170346a(22) =194649a(23) =221160a(24) =249975a(25) =281190a(26) =314901a(27) =351204a(28) =390195a(29) =431970