Sum of next n squares.

Terms

a(0) =1a(1) =13a(2) =77a(3) =294a(4) =855a(5) =2071a(6) =4403a(7) =8492a(8) =15189a(9) =25585a(10) =41041a(11) =63218a(12) =94107a(13) =136059a(14) =191815a(15) =264536a(16) =357833a(17) =475797a(18) =623029a(19) =804670a(20) =1026431a(21) =1294623a(22) =1616187a(23) =1998724a(24) =2450525a(25) =2980601a(26) =3598713a(27) =4315402a(28) =5142019a(29) =6090755