login
A321247
Number of maximal independent vertex sets in the n X n fiveleaper graph.
1
1, 1, 1, 1, 16, 1540, 176460, 6332072, 81841692, 2434154301, 124866787929
OFFSET
1,5
LINKS
Eric Weisstein's World of Mathematics, Fiveleaper Graph.
Eric Weisstein's World of Mathematics, Maximal Independent Vertex Set.
MATHEMATICA
Table[Length@FindIndependentVertexSet[RelationGraph[EuclideanDistance[##] == 5 &, Tuples[Range[n], 2]], Infinity, All], {n, 8}]
PROG
(Python)
from networkx import empty_graph, find_cliques, complement
def A321247(n):
G = empty_graph((i, j) for i in range(n) for j in range(n))
G.add_edges_from(((i, j), (i+k, j+l)) for i in range(n) for j in range(n) for (k, l) in ((5, 0), (-5, 0), (0, 5), (0, -5), (3, 4), (3, -4), (-3, 4), (-3, -4), (4, 3), (4, -3), (-4, 3), (-4, -3)) if 0<=i+k<n and 0<=j+l<n)
return sum(1 for c in find_cliques(complement(G))) # Chai Wah Wu, Jan 11 2024
CROSSREFS
Sequence in context: A266156 A054947 A071900 * A145406 A307924 A263387
KEYWORD
nonn,more
AUTHOR
Eric W. Weisstein, Nov 01 2018
EXTENSIONS
a(10) from Chai Wah Wu, Jan 17 2024
a(11) from Eric W. Weisstein, Jan 29 2024
STATUS
approved