a(n) = n^5 - (65/6)*n^4 + (173/6)*n^3 + (148/3)*n^2 - (862/3)*n + 265.

Terms

a(0) =1a(1) =20a(2) =281a(3) =1357a(4) =4281a(5) =10666a(6) =22825a(7) =43891a(8) =77937a(9) =130096a(10) =206681a(11) =315305a(12) =465001a(13) =666342a(14) =931561a(15) =1274671a(16) =1711585a(17) =2260236a(18) =2940697a(19) =3775301a(20) =4788761a(21) =6008290a(22) =7463721a(23) =9187627a(24) =11215441a(25) =13585576a(26) =16339545a(27) =19522081a(28) =23181257a(29) =27368606