Number of solutions to x^2 + y^2 + z^2 + w^2 <= n^2, where x, y, z, w are positive odd integers.

Terms

a(0) =0a(1) =0a(2) =1a(3) =1a(4) =5a(5) =11a(6) =32a(7) =44a(8) =82a(9) =120a(10) =207a(11) =277a(12) =405a(13) =541a(14) =768a(15) =966a(16) =1272a(17) =1592a(18) =2087a(19) =2489a(20) =3103a(21) =3719a(22) =4588a(23) =5348a(24) =6386a(25) =7522a(26) =8891a(27) =10175a(28) =11909a(29) =13623