Numerator of n*(n-2)*(2*n-1)/(2*(n-1)).

Terms

a(0) =0a(1) =15a(2) =28a(3) =135a(4) =132a(5) =455a(6) =360a(7) =1071a(8) =760a(9) =2079a(10) =1380a(11) =3575a(12) =2268a(13) =5655a(14) =3472a(15) =8415a(16) =5040a(17) =11951a(18) =7020a(19) =16359a(20) =9460a(21) =21735a(22) =12408a(23) =28175a(24) =15912a(25) =35775a(26) =20020a(27) =44631a(28) =24780a(29) =54839