Squares of odd square pyramidal numbers.

Terms

a(0) =1a(1) =25a(2) =3025a(3) =8281a(4) =81225a(5) =148225a(6) =670761a(7) =1030225a(8) =3186225a(9) =4447881a(10) =10962721a(11) =14402025a(12) =30525625a(13) =38452401a(14) =73188025a(15) =89397025a(16) =156975841a(17) =187279225a(18) =308880625a(19) =361722361a(20) =567440041a(21) =654592225a(22) =985646025a(23) =1122987121a(24) =1634180625a(25) =1842555625a(26) =2604979521a(27) =2911142025