a(n) = 361*n^2 - 19.

Terms

a(0) =342a(1) =1425a(2) =3230a(3) =5757a(4) =9006a(5) =12977a(6) =17670a(7) =23085a(8) =29222a(9) =36081a(10) =43662a(11) =51965a(12) =60990a(13) =70737a(14) =81206a(15) =92397a(16) =104310a(17) =116945a(18) =130302a(19) =144381a(20) =159182a(21) =174705a(22) =190950a(23) =207917a(24) =225606a(25) =244017a(26) =263150a(27) =283005a(28) =303582a(29) =324881