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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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Ben Kane and Zhi-Wei Sun, On almost universal mixed sums of squares and triangular numbers, arXiv:0808.2761
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 *)
CROSSREFS
Sequence in context: A032931 A072483 A081539 * A010097 A103761 A286241
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Sep 05 2008
STATUS
approved

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Last modified March 28 09:04 EDT 2024. Contains 371240 sequences. (Running on oeis4.)