The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A007787 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A007787

Number of nonintersecting rook paths joining opposite corners of 5 X n board.
(history; published version)

#26 by Michel Marcus at Mon Apr 06 06:29:11 EDT 2020

STATUS

reviewed

approved

#25 by Joerg Arndt at Mon Apr 06 06:25:13 EDT 2020

STATUS

proposed

reviewed

#24 by Seiichi Manyama at Mon Apr 06 04:49:56 EDT 2020

STATUS

editing

proposed

#23 by Seiichi Manyama at Mon Apr 06 04:46:09 EDT 2020

PROG

print([A007787(n) for n in range(1, 20)]) # _Seiichi Manyama_, Apr 06 2020

#22 by Seiichi Manyama at Mon Apr 06 04:40:14 EDT 2020

LINKS

Seiichi Manyama, <a href="/A007787/b007787.txt">Table of n, a(n) for n = 1..1000</a>

#21 by Seiichi Manyama at Mon Apr 06 04:34:29 EDT 2020

PROG

(Python)

# Using graphillion

from graphillion import GraphSet

import graphillion.tutorial as tl

def A064298(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)

return paths.len()

def A007787(n):

return A064298(n, 5)

print([A007787(n) for n in range(1, 20)])

#20 by Seiichi Manyama at Mon Apr 06 04:33:37 EDT 2020

DATA

1, 16, 125, 976, 8512, 79384, 752061, 7110272, 67005561, 630588698, 5933085772, 55827318685, 525343024814, 4943673540576, 46521924780255, 437788749723725, 4119750109152730, 38768318191017931, 364823700357765771, 3433121323699285343

STATUS

approved

editing

#19 by N. J. A. Sloane at Tue Jan 01 06:31:05 EST 2019

LINKS

F. Faase, <a href="http://www.iwriteiam.nl/counting.html">Counting Hamilton Hamiltonian cycles in product graphs</a>

Discussion

Tue Jan 01

06:31

OEIS Server: https://oeis.org/edit/global/2784

#18 by Susanna Cuyler at Tue Jan 09 17:55:46 EST 2018

STATUS

proposed

approved

#17 by Rachel Barnett at Tue Jan 09 15:39:53 EST 2018

STATUS

editing

proposed