13 times hexagonal numbers: a(n) = 13*n*(2*n-1).

Terms

a(0) =0a(1) =13a(2) =78a(3) =195a(4) =364a(5) =585a(6) =858a(7) =1183a(8) =1560a(9) =1989a(10) =2470a(11) =3003a(12) =3588a(13) =4225a(14) =4914a(15) =5655a(16) =6448a(17) =7293a(18) =8190a(19) =9139a(20) =10140a(21) =11193a(22) =12298a(23) =13455a(24) =14664a(25) =15925a(26) =17238a(27) =18603a(28) =20020a(29) =21489