1,2

Table of n, a(n) for n=1..4.

Eric Weisstein's World of Mathematics, Connected Graph

Eric Weisstein's World of Mathematics, Grid Graph

Eric Weisstein's World of Mathematics, Vertex-Induced Subgraph

Sequence in context: A290757 A012021 A175558 * A308280 A259086 A062518

Adjacent sequences: A289740 A289741 A289742 * A289744 A289745 A289746

nonn,hard,more

Eric W. Weisstein, Jul 11 2017

a(4) from Andrew Howroyd, Aug 15 2017

approved