A256465 - OEIS

%I #7 Apr 02 2015 05:22:28

%S 3,7,9,11,17,21,21,23,27,33,37,37,41,45,45,47,53,59,61,65,69,69,69,69,

%T 75,85,89,89,93,97,97,99,101,105,109,111,117,121,121,125,133,137,137,

%U 137,141,145,145,145,147,155,161,165,173,177,177,177,177,181,185

%N Number of points in a circle of squared radius n, points on the circle counted half.

%H S. W. P. Steen, <a href="http://dx.doi.org/10.1093/qmath/os-1.1.232">An expression for the number of lattice-points in a circle</a>, Q. J. Math. 1 (1930) 232-235.

%F a(n) = A057655(n) - A004018(n)/2.

%Y Cf. A057655, A004018.

%K nonn,easy

%O 1,1

%A _R. J. Mathar_, Mar 30 2015