A141491 Conjectured to be complete list of numbers not of the form 5*x^2 + 3*triangular number + 2*triangular number.

1, 4, 13, 19, 27, 46, 73, 97, 111, 123, 151, 168

Offset

1,2

Links

Table of n, a(n) for n=1..12.

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 == 5x^2 + 3y(y+1)/2 + 2z(z+1)/2, {x, y, z}, Integers] == {}, Print[n]; Sow[n]]]][[2, 1]] (* Jean-François Alcover, Oct 01 2018 *)

Crossrefs

Cf. A141464, A141497.

Cf. A141273, A141386, A141423, A141428, A141443, A141463.

Sequence in context: A371636 A075327 A267767 * A292363 A119048 A241264

Adjacent sequences: A141488 A141489 A141490 * A141492 A141493 A141494

Keyword

nonn

Author

N. J. A. Sloane, Sep 05 2008

Status

approved