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A333584
Number of Hamiltonian paths in a 9 X n grid starting at the lower left corner and finishing in the upper right corner.
3
1, 1, 128, 624, 28417, 286395, 8261289, 114243216, 2688307514, 43598351250, 928370853748, 16331387665387, 330593938169845, 6062963019120077, 119575303856316650, 2240422461856052342, 43592076562463162280, 825830699757513748579, 15955080499901505066753
OFFSET
1,3
PROG
(Python)
# Using graphillion
from graphillion import GraphSet
import graphillion.tutorial as tl
def A333580(n, k):
if n == 1 or k == 1: return 1
universe = tl.grid(n - 1, k - 1)
GraphSet.set_universe(universe)
start, goal = 1, k * n
paths = GraphSet.paths(start, goal, is_hamilton=True)
return paths.len()
def A333584(n):
return A333580(n, 9)
print([A333584(n) for n in range(1, 20)])
CROSSREFS
Row n=9 of A333580.
Cf. A014584.
Sequence in context: A198072 A197906 A218903 * A349110 A366827 A297463
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Mar 27 2020
STATUS
approved