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

Terms

a(0) =1a(1) =5a(2) =19a(3) =43a(4) =77a(5) =121a(6) =175a(7) =239a(8) =313a(9) =397a(10) =491a(11) =595a(12) =709a(13) =833a(14) =967a(15) =1111a(16) =1265a(17) =1429a(18) =1603a(19) =1787a(20) =1981a(21) =2185a(22) =2399a(23) =2623a(24) =2857a(25) =3101a(26) =3355a(27) =3619a(28) =3893a(29) =4177