login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A333581 Number of Hamiltonian paths in a 6 X (2n+1) grid starting at the lower left corner and finishing in the upper right corner. 3
1, 16, 378, 10204, 286395, 8142184, 232408228, 6641558434, 189856823709, 5427696641303 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..9.

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 A333581(n):

    return A333580(6, 2 * n + 1)

print([A333581(n) for n in range(10)])

CROSSREFS

Cf. A014523, A333580.

Sequence in context: A241106 A027403 A264073 * A201617 A235672 A235729

Adjacent sequences:  A333578 A333579 A333580 * A333582 A333583 A333584

KEYWORD

nonn,more

AUTHOR

Seiichi Manyama, Mar 27 2020

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 20 05:54 EDT 2021. Contains 348099 sequences. (Running on oeis4.)