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A333604 Number of directed Hamiltonian walks from NW to SW corners of an 8 X n grid. 2
1, 1, 64, 264, 6820, 52387, 909009, 8934966, 130373192, 1440623260, 19338414411 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..11.

PROG

(Python)

# Using graphillion

from graphillion import GraphSet

import graphillion.tutorial as tl

def A271592(n, k):

    if k == 1: return 1

    universe = tl.grid(k - 1, n - 1)

    GraphSet.set_universe(universe)

    start, goal = 1, n

    paths = GraphSet.paths(start, goal, is_hamilton=True)

    return paths.len()

def A333604(n):

    return A271592(8, n)

print([A333604(n) for n in range(1, 9)])

CROSSREFS

Row n=8 of A271592.

Cf. A333583.

Sequence in context: A255662 A045029 A231528 * A259406 A029873 A218069

Adjacent sequences:  A333601 A333602 A333603 * A333605 A333606 A333607

KEYWORD

nonn,more

AUTHOR

Seiichi Manyama, Mar 28 2020

STATUS

approved

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Last modified December 7 07:38 EST 2021. Contains 349571 sequences. (Running on oeis4.)