OFFSET
1,2
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..16
Eric Weisstein's World of Mathematics, King Graph
Eric Weisstein's World of Mathematics, Vertex-Induced Subgraph
MATHEMATICA
Table[If[n<2, n, g = GraphData[{"King", {n, n}}]; -1 + ParallelSum[ Boole@ ConnectedGraphQ@ Subgraph[g, s], {s, Subsets@ Range[n^2]}]], {n, 4}]
CROSSREFS
KEYWORD
nonn,hard
AUTHOR
Giovanni Resta, May 03 2017
EXTENSIONS
a(10)-a(13) from Andrew Howroyd, May 20 2017
STATUS
approved