0,3

See A255238 for a Gauss' circle problem comment and a link.

Table of n, a(n) for n=0..64.

a(n) = sum((-1)^m*T(n, m), m = 0..n), n >= 0, with T(n, m) = A255238(n, m) = 1 + floor(sqrt(n^2 - m^2)).

Cf. A255238.

Sequence in context: A140605 A049878 A038203 * A316339 A186971 A329255

Adjacent sequences: A255236 A255237 A255238 * A255240 A255241 A255242

nonn,easy

Wolfdieter Lang, Mar 12 2015

approved