Number of solutions to x^2 + y^2 + z^2 + t^2 == n (mod 2*n) for x,y,z,t in [0, 2*n).

Terms

a(0) =8a(1) =96a(2) =264a(3) =384a(4) =1160a(5) =3168a(6) =3080a(7) =1536a(8) =7560a(9) =13920a(10) =11528a(11) =12672a(12) =18824a(13) =36960a(14) =38280a(15) =6144a(16) =41480a(17) =90720a(18) =57608a(19) =55680a(20) =101640a(21) =138336a(22) =101384a(23) =50688a(24) =149000a(25) =225888a(26) =208008a(27) =147840a(28) =201608a(29) =459360