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

Terms

a(0) =2a(1) =2a(2) =6a(3) =14a(4) =26a(5) =42a(6) =62a(7) =86a(8) =114a(9) =146a(10) =182a(11) =222a(12) =266a(13) =314a(14) =366a(15) =422a(16) =482a(17) =546a(18) =614a(19) =686a(20) =762a(21) =842a(22) =926a(23) =1014a(24) =1106a(25) =1202a(26) =1302a(27) =1406a(28) =1514a(29) =1626