Number of solutions to +- 1^2 +- 2^2 +- 3^2 +- ... +- n^2 = n^2.

Terms

a(0) =1a(1) =1a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =0a(8) =2a(9) =3a(10) =0a(11) =0a(12) =5a(13) =15a(14) =0a(15) =0a(16) =127a(17) =184a(18) =0a(19) =0a(20) =819a(21) =1382a(22) =0a(23) =0a(24) =9441a(25) =18176a(26) =0a(27) =0a(28) =96562a(29) =172371