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

Terms

a(0) =0a(1) =7a(2) =42a(3) =129a(4) =292a(5) =555a(6) =942a(7) =1477a(8) =2184a(9) =3087a(10) =4210a(11) =5577a(12) =7212a(13) =9139a(14) =11382a(15) =13965a(16) =16912a(17) =20247a(18) =23994a(19) =28177a(20) =32820a(21) =37947a(22) =43582a(23) =49749a(24) =56472a(25) =63775a(26) =71682a(27) =80217a(28) =89404a(29) =99267