If a circle is centered on the origin and has radius r, it may pass through some points with integer coordinates. In fact, by symmetry, this will be a multiple of 4.

Find the smallest radius that will pass through 4n integer points where n=1,2,3,4,5.

Feel free to go further.

(In reply to OEIS sequence by Brian Smith)

 

The correct sequence is NOT the one you quote:

Sloane:  A018782

Please  compare a(5) and on.

Edited on March 1, 2011, 4:52 pm

Posted by Ady TZIDON on 2011-03-01 16:37:47