Number of squares in an n X n grid of squares with diagonals.

Terms

a(0) =1a(1) =10a(2) =31a(3) =72a(4) =137a(5) =234a(6) =367a(7) =544a(8) =769a(9) =1050a(10) =1391a(11) =1800a(12) =2281a(13) =2842a(14) =3487a(15) =4224a(16) =5057a(17) =5994a(18) =7039a(19) =8200a(20) =9481a(21) =10890a(22) =12431a(23) =14112a(24) =15937a(25) =17914a(26) =20047a(27) =22344a(28) =24809a(29) =27450