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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Seiichi Manyama, Table of n, a(n) for n = 1..500

Index entries for sequences related to graphs, Hamiltonian

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

Adjacent sequences:  A333579 A333580 A333581 * A333583 A333584 A333585

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Mar 27 2020

STATUS

approved

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Last modified May 19 12:20 EDT 2022. Contains 353833 sequences. (Running on oeis4.)