A141386 Conjectured to be complete list of numbers not of the form x^2 + y^2 + 5*triangular number.

3, 11, 12, 27, 129, 138, 273

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 <= 300, n++, If[FindInstance[n == x^2 + y^2 + 5z(z+1)/2, {x, y, z}, Integers] == {}, Print[n]; Sow[n]]]][[2, 1]] (* Jean-François Alcover, Oct 01 2018 *)

Crossrefs

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

Cf. A141464, A141491, A141497.

Sequence in context: A101134 A045110 A055046 * A254220 A119231 A177335

Adjacent sequences: A141383 A141384 A141385 * A141387 A141388 A141389

Keyword

nonn

Author

N. J. A. Sloane, Sep 05 2008

Status

approved