a(n) = 5n^4 - 4n^3 + 3n^2 - 2n + 1.

Terms

a(0) =1a(1) =3a(2) =57a(3) =319a(4) =1065a(5) =2691a(6) =5713a(7) =10767a(8) =18609a(9) =30115a(10) =46281a(11) =68223a(12) =97177a(13) =134499a(14) =181665a(15) =240271a(16) =312033a(17) =398787a(18) =502489a(19) =625215a(20) =769161a(21) =936643a(22) =1130097a(23) =1352079a(24) =1605265a(25) =1892451a(26) =2216553a(27) =2580607a(28) =2987769a(29) =3441315