%I A000224
%S A000224 1,2,2,2,3,4,4,3,4,6,6,4,7,8,6,4,9,8,10,6,8,12,12,6,11,14,
%T A000224 11,8,15,12,16,7,12,18,12,8,19,20,14,9,21,16,22,12,12,24,
%U A000224 24,8,22,22,18,14,27,22,18,12,20,30,30,12,31,32,16,12,21
%N A000224 Number of squares mod n.
%D A000224 E. J. F. Primrose, The number of quadratic residues mod m, Math. Gaz. 
               v. 61 (1977) n. 415, 60-61.
%D A000224 W. D. Stangl, Counting squares in Z_n, Math. Mag. 69 (1996) 285-289.
%H A000224 T. D. Noe, <a href="b000224.txt">Table of n, a(n) for n=1..10000</a>
%H A000224 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).
%F A000224 Multiplicative with a(p^e) = [p^e/6]+2 if p = 2; [p^(e+1)/(2p+2)]+1 if 
               p > 2. - David W. Wilson (davidwwilson(AT)comcast.net), Aug 01, 2001.
%p A000224 seq(nops({seq(n^2 mod k,n=1..100)}),k=1..65); (E. Deutsch)
%o A000224 (PARI) a(n) = local(v,i); v = vector(n,i,0); for(i=0, floor(n/2),v[i^2%n+1] 
               = 1); sum(i=1,n,v[i]) - Franklin T. Adams-Watters, Nov 05 2006
%Y A000224 a(n)=A105612(n)+1.
%Y A000224 Sequence in context: A144000 A085202 A096009 this_sequence A085201 A051601 
               A054225
%Y A000224 Adjacent sequences: A000221 A000222 A000223 this_sequence A000225 A000226 
               A000227
%K A000224 nonn,easy,nice,mult
%O A000224 1,2
%A A000224 N. J. A. Sloane (njas(AT)research.att.com).