a(n) = n*(n+1)*(14*n-11)/6.

Terms

a(0) =0a(1) =1a(2) =17a(3) =62a(4) =150a(5) =295a(6) =511a(7) =812a(8) =1212a(9) =1725a(10) =2365a(11) =3146a(12) =4082a(13) =5187a(14) =6475a(15) =7960a(16) =9656a(17) =11577a(18) =13737a(19) =16150a(20) =18830a(21) =21791a(22) =25047a(23) =28612a(24) =32500a(25) =36725a(26) =41301a(27) =46242a(28) =51562a(29) =57275