Sum of squares of first n quarter-squares (A002620).

Terms

a(0) =0a(1) =0a(2) =1a(3) =5a(4) =21a(5) =57a(6) =138a(7) =282a(8) =538a(9) =938a(10) =1563a(11) =2463a(12) =3759a(13) =5523a(14) =7924a(15) =11060a(16) =15156a(17) =20340a(18) =26901a(19) =35001a(20) =45001a(21) =57101a(22) =71742a(23) =89166a(24) =109902a(25) =134238a(26) =162799a(27) =195923a(28) =234339a(29) =278439