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A333605 Number of directed Hamiltonian walks from NW to SW corners of a 9 X (2*n+1) grid. 1
1, 128, 28002, 7503654, 2087813834, 585874869236, 164719994049404, 46331085939142414, 13032851914297031372, 3666193548666012258524, 1031319586988812684556890, 290115923359022569718438776, 81611236566429170178900484740, 22957699681804739055041075650848 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Seiichi Manyama, Table of n, a(n) for n = 0..200

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 A333605(n):

    return A271592(9, 2 * n + 1)

print([A333605(n) for n in range(15)])

CROSSREFS

Row n=9 of A271592 (with 0 omitted).

Cf. A333584.

Sequence in context: A051251 A264346 A189958 * A264189 A264076 A067822

Adjacent sequences:  A333602 A333603 A333604 * A333606 A333607 A333608

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Mar 28 2020

STATUS

approved

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Last modified January 21 16:03 EST 2022. Contains 350479 sequences. (Running on oeis4.)