1+2n+3n^2+4n^3+5n^4.

Terms

a(0) =1a(1) =15a(2) =129a(3) =547a(4) =1593a(5) =3711a(6) =7465a(7) =13539a(8) =22737a(9) =35983a(10) =54321a(11) =78915a(12) =111049a(13) =152127a(14) =203673a(15) =267331a(16) =344865a(17) =438159a(18) =549217a(19) =680163a(20) =833241a(21) =1010815a(22) =1215369a(23) =1449507a(24) =1715953a(25) =2017551a(26) =2357265a(27) =2738179a(28) =3163497a(29) =3636543