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A333582
Number of Hamiltonian paths in a 7 X n grid starting at the lower left corner and finishing in the upper right corner.
3
1, 1, 32, 111, 1670, 10204, 111712, 851073, 8261289, 68939685, 637113287, 5521505724, 49977297839, 440051896440, 3947537767621, 34992551369200, 312684850861298, 2779712414621925, 24796726969942763, 220708765035288988, 1967401456946216789, 17520501580778152908
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 A333582(n):
return A333580(n, 7)
print([A333582(n) for n in range(1, 25)])
CROSSREFS
Row n=7 of A333580.
Cf. A014584.
Sequence in context: A337786 A233684 A218068 * A039464 A203728 A044283
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Mar 27 2020
STATUS
approved