a(n) = n^4 - n^3 + n^2 - n + 1.

Terms

a(0) =1a(1) =1a(2) =11a(3) =61a(4) =205a(5) =521a(6) =1111a(7) =2101a(8) =3641a(9) =5905a(10) =9091a(11) =13421a(12) =19141a(13) =26521a(14) =35855a(15) =47461a(16) =61681a(17) =78881a(18) =99451a(19) =123805a(20) =152381a(21) =185641a(22) =224071a(23) =268181a(24) =318505a(25) =375601a(26) =440051a(27) =512461a(28) =593461a(29) =683705