OFFSET
2,1
COMMENTS
Schinzel proved such a circle always exists, and the square of the radius of a circle passing through 3 integral points is always rational so the sequence is well-defined.
LINKS
S. S. Lacerda, schinzel.py
E. Pegg, Lattice Circles
Jim Randell, A collection of minimal radius lattice circles (github)
C. Schinzel, Sur l'existence d'un cercle passant par un nombre donné de points aux coordonnées entières, Enseignement Math, vol. 4, pp. 71-72, 1958.
EXAMPLE
For n=3 a minimal circle is (x - 1/6)^2 + (y - 1/6)^2 = 25/18.
CROSSREFS
KEYWORD
nonn,nice,hard,frac
AUTHOR
Sofia Lacerda, May 04 2022
EXTENSIONS
Data corrected by Sean A. Irvine, Jul 19 2022
a(29)-a(33) from Jim Randell, Jan 10 2023
STATUS
approved