%I A057961
%S A057961 1,5,9,13,21,25,29,37,45,49,57,61,69,81,89,97,101,109,113,121,129,137,
%T A057961 145,149,161,169,177,185,193,197,213,221,225,233,241,249,253,261,277,
%U A057961 285,293,301,305,317,325,333,341,349,357,365,373,377,385,401,405,421
%N A057961 Number of points in square lattice covered by a disc centered at (0,0) 
               as its radius increases.
%C A057961 Useful for rasterizing circles.
%D A057961 J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", 
               Springer-Verlag, p. 106.
%H A057961 T. D. Noe, <a href="b057961.txt">Table of n, a(n) for n=1..1000</a>
%e A057961 a(2)=5 because (0,0); (0,1); (0,-1); (1,0); (-1,0) are covered by any 
               disc of radius between 1 and sqrt(2).
%Y A057961 Cf. A004018, A004020, A005883, A057962. Distinct terms of A057655.
%Y A057961 Sequence in context: A046586 A023493 A087461 this_sequence A089217 A166049 
               A053411
%Y A057961 Adjacent sequences: A057958 A057959 A057960 this_sequence A057962 A057963 
               A057964
%K A057961 easy,nonn
%O A057961 1,2
%A A057961 Ken Takusagawa (kenta(AT)cs.stanford.edu), Oct 15 2000