a(n) = (2*n+1)*(3*n+1)*(4*n+1).

Terms

a(0) =1a(1) =60a(2) =315a(3) =910a(4) =1989a(5) =3696a(6) =6175a(7) =9570a(8) =14025a(9) =19684a(10) =26691a(11) =35190a(12) =45325a(13) =57240a(14) =71079a(15) =86986a(16) =105105a(17) =125580a(18) =148555a(19) =174174a(20) =202581a(21) =233920a(22) =268335a(23) =305970a(24) =346969a(25) =391476a(26) =439635a(27) =491590a(28) =547485