1,5

Table of n, a(n) for n=1..26.

Three collinear points in an n X n grid A000938 ; n X n X n grid A157882

Sequence in context: A236981 A203724 A006915 * A183751 A231954 A224338

Adjacent sequences: A178267 A178268 A178269 * A178271 A178272 A178273

nonn

R. H. Hardin, suggested by R. J. Mathar in the Sequence Fans Mailing List, May 24 2010

approved