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

Terms

a(0) =2a(1) =15a(2) =50a(3) =119a(4) =234a(5) =407a(6) =650a(7) =975a(8) =1394a(9) =1919a(10) =2562a(11) =3335a(12) =4250a(13) =5319a(14) =6554a(15) =7967a(16) =9570a(17) =11375a(18) =13394a(19) =15639a(20) =18122a(21) =20855a(22) =23850a(23) =27119a(24) =30674a(25) =34527a(26) =38690a(27) =43175a(28) =47994a(29) =53159