%I A057962
%S A057962 4,12,16,24,32,44,52,60,68,76,80,88,96,112,120,124,140,148,156,164,172,
%T A057962 180,188,192,208,216,232,240,248,256,268,276,284,300,308,316,332,348,
%U A057962 360,368,376,384,392,400,408,424,432,440,448,460,468,484,492,500
%N A057962 Number of points (x,y) in square lattice with (x-1/2)^2+(y-1/2)^2 <= 
               n.
%C A057962 Always a multiple of 4. Useful for rasterizing circles.
%D A057962 J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", 
               Springer-Verlag, p. 106.
%e A057962 a(2)=12 because (-1,0); (-1,1); (0,-1); (0,0); (0,1); (0,2); (1,-1); 
               (1,0); (1,1); (1,2); (2,0); (2,1) are covered by any disc of radius 
               between sqrt(2.5) and sqrt(4.5) and centered at (0.5,0.5).
%Y A057962 Cf. A057961, A004018, A004020. Partial sums of A005883.
%Y A057962 Sequence in context: A108269 A081523 A053006 this_sequence A073687 A090818 
               A075191
%Y A057962 Adjacent sequences: A057959 A057960 A057961 this_sequence A057963 A057964 
               A057965
%K A057962 easy,nonn
%O A057962 1,1
%A A057962 Ken Takusagawa (kenta(AT)cs.stanford.edu), Oct 15 2000