

A071339


a(n) = the maximum number of lattice points touched by an origincentered circle with radius <= n.


9



1, 4, 4, 8, 8, 12, 12, 12, 12, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 36, 36, 36
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

0,2


LINKS

Table of n, a(n) for n=0..67.
Hugo Pfoertner, FORTRAN program for A071339A071347


FORMULA

a(n) = max(i=0 to n^2) A004018(i)


EXAMPLE

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).


CROSSREFS

Cf. A004018, A071339A071347, A071383A071385.
Sequence in context: A196054 A292135 A053249 * A146890 A168273 A278933
Adjacent sequences: A071336 A071337 A071338 * A071340 A071341 A071342


KEYWORD

easy,nonn


AUTHOR

Hugo Pfoertner, May 22 2002


EXTENSIONS

Edited by Don Reble, Nov 06 2005


STATUS

approved



