1,2
Table of n, a(n) for n=1..3.
Eric Weisstein's World of Mathematics, Chromatic Invariant
Eric Weisstein's World of Mathematics, Grid Graph
Sequence in context: A022011 A175889 A347849 * A022545 A346996 A086503
Adjacent sequences: A295170 A295171 A295172 * A295174 A295175 A295176
nonn,more
Eric W. Weisstein, Nov 16 2017
approved