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A022556 Numbers that are a sum of a square and 2 nonnegative cubes. 0

%I

%S 0,1,2,3,4,5,6,8,9,10,11,12,13,16,17,18,20,24,25,26,27,28,29,31,32,33,

%T 34,35,36,37,38,39,41,43,44,45,49,50,51,52,53,54,55,57,58,60,63,64,65,

%U 66,68,69,70,71,72,73,74,76,77,79,80,81,82,83,84,88,89,90,91,92,95,97,99,100

%N Numbers that are a sum of a square and 2 nonnegative cubes.

%p isA022556 := proc(n)

%p local a2,b,c ;

%p for b from 0 do

%p if b^3 > n then

%p return false;

%p end if;

%p for c from b do

%p a2 := n-b^3-c^3 ;

%p if a2 < 0 then

%p break;

%p end if;

%p if issqr(a2) then

%p return true;

%p end if;

%p end do:

%p end do:

%p end proc: # _R. J. Mathar_, Sep 02 2016

%t r[n_] := Reduce[i >= 0 && j >= 0 && k >= j && n == i^2 + j^3 + k^3, {i, j, k}, Integers];

%t Select[Range[0, 100], r[#] =!= False&] (* _Jean-Fran├žois Alcover_, Apr 07 2020 *)

%K nonn

%O 1,3

%A _N. J. A. Sloane_.

%E More terms from _Jean-Fran├žois Alcover_, Apr 07 2020

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Last modified September 28 17:43 EDT 2020. Contains 337393 sequences. (Running on oeis4.)