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A141491 Conjectured to be complete list of numbers not of the form 5*x^2 + 3*triangular number + 2*triangular number. 8

%I #11 Oct 01 2018 03:58:12

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

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

%H Ben Kane and Zhi-Wei Sun, <a href="http://arxiv.org/abs/0808.2761">On almost universal mixed sums of squares and triangular numbers</a>, arXiv:0808.2761

%t 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 *)

%Y Cf. A141464, A141497.

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

%K nonn

%O 1,2

%A _N. J. A. Sloane_, Sep 05 2008

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Last modified August 17 05:44 EDT 2024. Contains 375200 sequences. (Running on oeis4.)