a(n) = (n-1)*(n+2)*(2*n+11)/2.

Terms

a(0) =0a(1) =30a(2) =85a(3) =171a(4) =294a(5) =460a(6) =675a(7) =945a(8) =1276a(9) =1674a(10) =2145a(11) =2695a(12) =3330a(13) =4056a(14) =4879a(15) =5805a(16) =6840a(17) =7990a(18) =9261a(19) =10659a(20) =12190a(21) =13860a(22) =15675a(23) =17641a(24) =19764a(25) =22050a(26) =24505a(27) =27135a(28) =29946a(29) =32944