A141423 Conjectured to be complete list of numbers not of the form 3*x^2 + 4*y^2 + triangular number.

2, 11, 23, 50, 116, 135, 138

Offset

1,1

Links

Table of n, a(n) for n=1..7.

Ben Kane and Zhi-Wei Sun, On almost universal mixed sums of squares and triangular numbers, arXiv:0808.2761

Mathematica

Reap[For[n = 1, n <= 200, n++, If[FindInstance[n == 3x^2 + 4y^2 + z(z+1)/2, {x, y, z}, Integers] == {}, Print[n]; Sow[n]]]][[2, 1]] (* Jean-François Alcover, Oct 01 2018 *)

Crossrefs

Cf. A141273, A141386, A141428, A141443, A141463.

Cf. A141464, A141491, A141497.

Sequence in context: A126916 A090424 A056637 * A344032 A338225 A106974

Adjacent sequences: A141420 A141421 A141422 * A141424 A141425 A141426

Keyword

nonn

Author

N. J. A. Sloane, Sep 05 2008

Status

approved