%I #18 Oct 26 2023 00:14:41

%S 1,2,3,4,6,7,8,9,11,12,14,15,16,18,19,21,22,23,24,27,28,30,31,32,33,

%T 35,36,38,39,42,43,44,46,47,48,49,51,54,55,56,57,59,60,62,63,64,66,67,

%U 69,70,71,72,75,76,77,78,79

%N Numbers that are not the sum of 2 distinct nonzero squares.

%H Charles R Greathouse IV, <a href="/A004439/b004439.txt">Table of n, a(n) for n = 1..10000</a>

%H F. Smarandache, <a href="http://www.gallup.unm.edu/~smarandache/Definitions-book.pdf">Definitions, Solved and Unsolved Problems, Conjectures, ...</a>, edited by M. Perez, Xiquan Publishing House, 2000.

%H <a href="/index/Su#ssq">Index entries for sequences related to sums of squares</a>

%o (PARI) is(n)=if(n<5, return(1)); my(f=factor(n)%4); if(vecmin(f[,1])>1, return(1)); for(i=1,#f[,1], if(f[i,1]==3 && f[i,2]%2, return(1))); 0 \\ _Charles R Greathouse IV_, Jun 18 2013

%Y Complement of A004431.

%K nonn

%O 1,2

%A _N. J. A. Sloane_