A296101 Number of maximal cliques in the n-Keller graph.

4, 40, 6320, 318322976

Offset

1,1

Links

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

Eric Weisstein's World of Mathematics, Keller Graph

Eric Weisstein's World of Mathematics, Maximal Clique

Prog

(Python)
from itertools import zip_longest
from sympy.ntheory.factor_ import digits
from networkx import empty_graph, find_cliques
def A296101(n):
    k = 1<<(n<<1)
    G = empty_graph(range(k))
    G.add_edges_from((a, b) for a in range(k) for b in range(a) if (s:=tuple(c-d&3 for c, d in zip_longest(digits(a, 4)[-1:0:-1], digits(b, 4)[-1:0:-1], fillvalue=0))).count(2)>0 and s.count(0)<=len(s)-2)
    return sum(1 for c in find_cliques(G)) # Chai Wah Wu, Jan 11 2024

Crossrefs

Cf. A202604, A295902, A296100.

Sequence in context: A000841 A059918 A375141 * A002677 A119527 A074991

Adjacent sequences: A296098 A296099 A296100 * A296102 A296103 A296104

Keyword

nonn,hard,more

Author

Eric W. Weisstein, Dec 04 2017

Extensions

a(4) from Eric W. Weisstein, Nov 09 2018

Status

approved