(16n^6 - 24n^5 + 2n^4 + 11n^3 - 6n^2 + n) / 6.

Terms

a(0) =0a(1) =0a(2) =59a(3) =1040a(4) =7014a(5) =29580a(6) =94105a(7) =247884a(8) =570220a(9) =1184424a(10) =2271735a(11) =4087160a(12) =6977234a(13) =11399700a(14) =17945109a(15) =27360340a(16) =40574040a(17) =58723984a(18) =83186355a(19) =115606944a(20) =157934270a(21) =212454620a(22) =281829009a(23) =369132060a(24) =477892804a(25) =612137400a(26) =776433775a(27) =975938184a(28) =1216443690