The OEIS is supported by the many generous donors to the OEIS Foundation.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
%I #11 Jul 14 2024 03:51:12
%S 1,4,4,8,8,12,12,12,12,16,16,16,16,16,16,16,16,16,16,24,24,24,24,24,
%T 24,24,24,24,24,24,24,24,24,24,32,32,32,32,32,32,32,32,32,32,32,32,32,
%U 32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,36,36,36
%N a(n) = the maximum number of lattice points touched by an origin-centered circle with radius <= n.
%H Hugo Pfoertner, <a href="https://www.randomwalk.de/sequences/a071339.txt">FORTRAN program for A071339-A071347</a>
%F a(n) = max(i=0 to n^2) A004018(i)
%e a(5 to 8)=12 because the circle with radius 5 touches 12 lattice points: (+-1,+-2), (+-2,+-1), (+-5,0), (0,+-5); but no circle touches more, until the radius is sqrt(65).
%Y Cf. A004018, A071339-A071347, A071383-A071385.
%K easy,nonn
%O 0,2
%A _Hugo Pfoertner_, May 22 2002
%E Edited by _Don Reble_, Nov 06 2005