a(n) = 81*n^2 - 2247*n + 15383.

Terms

a(0) =15383a(1) =13217a(2) =11213a(3) =9371a(4) =7691a(5) =6173a(6) =4817a(7) =3623a(8) =2591a(9) =1721a(10) =1013a(11) =467a(12) =83a(13) =-139a(14) =-199a(15) =-97a(16) =167a(17) =593a(18) =1181a(19) =1931a(20) =2843a(21) =3917a(22) =5153a(23) =6551a(24) =8111a(25) =9833a(26) =11717a(27) =13763a(28) =15971a(29) =18341