OFFSET
1,1
COMMENTS
The size of the smallest set, the independent domination number, is given by A291297.
LINKS
Eric Weisstein's World of Mathematics, Maximal Independent Vertex Set
Eric Weisstein's World of Mathematics, Fibonacci Cube Graph
Wikipedia, Fibonacci cube
EXAMPLE
Case n=1: The vertices are 0, 1. Each singleton vertex set is a maximal independent set, so a(1) = 2.
Case n=2: The vertices are 00, 01, 10. Maximal independent sets are {00} and {01, 10}, so a(2) = 2.
Case n=3: The vertices are 000, 001, 010, 100, 101. Maximal independent sets are {000, 101}, {010, 101}, {001, 010, 100}, so a(3)=3.
PROG
(Python)
from itertools import combinations, product
from networkx import empty_graph, find_cliques
def A291742(n):
v = tuple(int(q, 2) for q in (''.join(p) for p in product('01', repeat=n)) if '11' not in q)
G = empty_graph(v)
e = tuple((a, b) for a, b in combinations(v, 2) if (lambda m: (m&-m)^m if m else 1)(a^b))
G.add_edges_from(e)
return sum(1 for c in find_cliques(G)) # Chai Wah Wu, Jan 14 2024
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Andrew Howroyd, Aug 30 2017
EXTENSIONS
a(9) from Pontus von Brömssen, Mar 06 2020
STATUS
approved