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A141273
Conjectured to be complete list of numbers not of the form 4*x^2 + 4*y^2 + triangular number.
9
2, 12, 13, 24, 27, 34, 54, 84, 112, 133, 162, 234, 237, 279, 342, 399, 652, 834, 864
OFFSET
1,1
MATHEMATICA
r[k_] := Reduce[x >= 0 && y >= 0 && z >= 0 && k == 4x^2 + 4y^2 + z(z+1)/2, {x, y, z}, Integers];
Reap[For[k=1, k <= 1000, k++, If[r[k]===False, Print[k]; Sow[k]]]][[2, 1]] (* Jean-François Alcover, Aug 31 2018 *)
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Sep 05 2008
STATUS
approved