%I A105612
%S A105612 0,1,1,1,2,3,3,2,3,5,5,3,6,7,5,3,8,7,9,5,7,11,11,5,10,13,10,7,14,11,15,
%T A105612 6,11,17,11,7,18,19,13,8,20,15,21,11,11,23,23,7,21,21,17,13,26,21,17,11,
%U A105612 19,29,29,11,30,31,15,11,20,23,33,17,23,23,35,11,36,37,21,19,23
%N A105612 Number of nonzero quadratic residues (mod n) (cf. A000224).
%D A105612 E. J. F. Primrose, The number of quadratic residues mod m, Math. Gaz. 
               v. 61 (1977) n. 415, 60-61.
%D A105612 W. D. Stangl, Counting squares in Z_n, Math. Mag. 69 (1996) 285-289.
%H A105612 S. R. Finch and Pascal Sebah, <a href="http://arXiv.org/abs/math.NT/0604465">
               Squares and Cubes Modulo n</a> (arXiv:math.NT/0604465).
%H A105612 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               QuadraticResidue.html">Quadratic Residue</a>
%Y A105612 a(n)=A000224(n)-1
%Y A105612 Sequence in context: A002963 A046677 A109747 this_sequence A141744 A089783 
               A090414
%Y A105612 Adjacent sequences: A105609 A105610 A105611 this_sequence A105613 A105614 
               A105615
%K A105612 nonn
%O A105612 1,5
%A A105612 Eric Weisstein (eric(AT)weisstein.com), Apr 15, 2005