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A022557 Numbers that are not the sum of a square and 2 nonnegative cubes.

%I A022557 #19 Jul 08 2025 09:17:23
%S A022557 7,14,15,19,21,22,23,30,40,42,46,47,48,56,59,61,62,67,75,78,85,86,87,
%T A022557 93,94,96,98,104,105,106,110,111,112,115,117,119,120,124,131,138,139,
%U A022557 143,147,157,159,163,166,167,173,176,180,181,183,184,187,194,195,199,200,202
%N A022557 Numbers that are not the sum of a square and 2 nonnegative cubes.
%H A022557 R. J. Mathar, <a href="/A022557/b022557.txt">Table of n, a(n) for n = 1..9477</a>
%p A022557 isA022557 := proc(n)
%p A022557     not isA022556(n) ;
%p A022557 end proc:
%p A022557 n := 1:
%p A022557 for c from 0 do
%p A022557     if isA022557(c) then
%p A022557         printf("%d %d\n",n,c);
%p A022557         n := n+1 ;
%p A022557     end if;
%p A022557 end do: # _R. J. Mathar_, Sep 02 2016
%t A022557 smax = 50000;
%t A022557 A022556 = Table[s = i^2 + j^3 + k^3; If[s <= smax, s, Nothing], {i, 0, Sqrt[smax] // Ceiling}, {j, 0, smax^(1/3) // Ceiling}, {k, j, smax^(1/3) // Ceiling}] // Flatten // Union;
%t A022557 Complement[Range[smax], A022556] (* _Jean-François Alcover_, Feb 20 2023 *)
%Y A022557 Cf. A022556 (complement).
%K A022557 nonn
%O A022557 1,1
%A A022557 _N. J. A. Sloane_