Number of solutions to Sum_{i=1..n} x_i^2 == 0 (mod 4) with x_i in 0..3.
A228920
Number of solutions to Sum_{i=1..n} x_i^2 == 0 (mod 4) with x_i in 0..3.
Terms
- a(0) =2a(1) =4a(2) =8a(3) =32a(4) =192a(5) =1024a(6) =4608a(7) =18432a(8) =69632a(9) =262144a(10) =1015808a(11) =4063232a(12) =16515072a(13) =67108864a(14) =270532608a(15) =1082130432a(16) =4311744512a(17) =17179869184a(18) =68585259008a(19) =274341036032
External references
- oeis: A228920