1 + 2*n^2 + 3*n^3 + 4*n^4 + 5*n^5 + 6*n^6 + 7*n^7 + 8*n^8.

Terms

a(0) =1a(1) =36a(2) =3585a(3) =73810a(4) =669921a(5) =3784176a(6) =15721201a(7) =52683870a(8) =150652545a(9) =381367036a(10) =876543201a(11) =1862778666a(12) =3709924705a(13) =6996023880a(14) =12592235601a(15) =21771494326a(16) =36344967681a(17) =58830704340a(18) =92659184065a(19) =142420804866a(20) =214160664801a(21) =315726318496