login
Integers not expressible as the sum of a positive triangular number and a square.
0

%I #9 Sep 18 2024 14:57:40

%S 8,9,13,18,20,23,27,33,34,38,41,43,47,48,58,60,62,63,68,69,73,76,83,

%T 86,88,89,90,93,97,98,99,108,111,112,113,118,123,125,132,133,134,135,

%U 138,139,143,144,146,148,151,158,160,163,164,167,168,173,174,177,181,182

%N Integers not expressible as the sum of a positive triangular number and a square.

%o (PARI) isok(n)={for(k=1, sqrtint(2*n), if(issquare(n-binomial(k+1,2)), return(0))); 1} \\ _Andrew Howroyd_, Sep 18 2024

%Y Cf. A000217, A000290, A014134.

%K nonn

%O 1,1

%A _Jason Earls_, Nov 14 2002

%E Name clarified and offset changed by _Andrew Howroyd_, Sep 18 2024