OFFSET
0,3
EXAMPLE
a(4)=13 because the largest circle with radius <= 4 to touch A071339(4)=8 points has radius sqrt(13).
PROG
(FORTRAN) See A071339.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Hugo Pfoertner, May 22 2002
EXTENSIONS
Edited by Don Reble, Nov 06 2005
STATUS
approved