144n^2 + 2n.

Terms

a(0) =146a(1) =580a(2) =1302a(3) =2312a(4) =3610a(5) =5196a(6) =7070a(7) =9232a(8) =11682a(9) =14420a(10) =17446a(11) =20760a(12) =24362a(13) =28252a(14) =32430a(15) =36896a(16) =41650a(17) =46692a(18) =52022a(19) =57640a(20) =63546a(21) =69740a(22) =76222a(23) =82992a(24) =90050a(25) =97396a(26) =105030a(27) =112952a(28) =121162a(29) =129660