%I
%S 5,8,13,17,20,25,29,32,37,40,41,45,52,53,61,65,68,72,73,80,85,89,97,
%T 100,101,104,109,113,116,117,125,128,136,137,145,148,149,153,157,160,
%U 164,169,173,180,181,185,193,197,200,205,208,212,221,225,229,232,233
%N Numbers that are both the sum of two nonzero squares and the difference of two nonzero squares.
%C Intersection of A000404 (sum of squares) and A024352 (difference of squares).
%C Also: Numbers of the form x^2+4y^2, where x and y are positive integers. Cf. A154777, A092572, A154778 for analogous sequences.  _M. F. Hasler_, Jan 24 2009
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/SumofSquaresFunction.html">Sum of Squares Function.</a>
%o (PARI) isA097268(n) = forstep( b=2,sqrtint(n1),2, issquare(nb^2) && return(1)) \\ _M. F. Hasler_, Jan 24 2009
%Y Cf. A000404, A024352, A097269A097271.
%K nonn
%O 1,1
%A _Ray Chandler_, Aug 19 2004
