login
A339119
Number of cycles in the grid graph P_7 X P_n.
2
21, 681, 23984, 692194, 18438929, 487150371, 12947640143, 345142437669, 9203308475041, 245355064111139, 6540331954247241, 174341025325354201, 4647322411026104632, 123881845810609904802, 3302270967098053652763, 88027348826922694314763, 2346510376337057464408514
OFFSET
2,1
COMMENTS
a(n+1) / a(n) tends to 26.65660630533835653493851570574867751479178653672292060740586256111131858... - Vaclav Kotesovec, Nov 24 2020
LINKS
Vaclav Kotesovec, Empirical g.f.
Eric Weisstein's World of Mathematics, Graph Cycle
Eric Weisstein's World of Mathematics, Grid Graph
PROG
(Python)
# Using graphillion
from graphillion import GraphSet
import graphillion.tutorial as tl
def A(n, k):
universe = tl.grid(n - 1, k - 1)
GraphSet.set_universe(universe)
cycles = GraphSet.cycles()
return cycles.len()
def A339119(n):
return A(n, 7)
print([A339119(n) for n in range(2, 15)])
CROSSREFS
Sequence in context: A006934 A211877 A212734 * A243746 A276021 A100713
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Nov 24 2020
STATUS
approved