cp's OEIS Frontend

A374092 Number of solutions to n = x^2 + x*y + y^2 with 0 < x < y.

%I A374092 #12 Jun 29 2024 10:43:17
%S A374092 0,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,0,1,0,0,1,0,0,
%T A374092 0,0,0,1,0,1,0,0,0,1,0,0,0,0,0,1,0,0,1,0,0,0,0,1,0,0,0,1,0,1,0,0,0,1,
%U A374092 0,0,0,0,0,1,0,0,1,0,0,1,0,0,0,0,1,0,0,0,0,0,0,2,0,1,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,1,1
%N A374092 Number of solutions to n = x^2 + x*y + y^2 with 0 < x < y.
%C A374092 a(n) = 0 if n == 2 (mod 4). - _Robert Israel_, Jun 28 2024
%p A374092 N:= 200: # for a(0) .. a(N)
%p A374092 V:= Array(0..N):
%p A374092 for x from 1 to floor(sqrt(N/3)) do
%p A374092   for y from x+1 do
%p A374092      v:= x^2 + x*y + y^2;
%p A374092      if v > N then break fi;
%p A374092      V[v]:= V[v]+1;
%p A374092 od od:
%p A374092 convert(V,list); # _Robert Israel_, Jun 28 2024
%Y A374092 Cf. A025441, A374093, A374094.
%K A374092 nonn
%O A374092 0,92
%A A374092 _Seiichi Manyama_, Jun 28 2024