The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A139670 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A139670

Number of n X n symmetric binary matrices with all row sums 4.
(history; published version)

#27 by Wesley Ivan Hurt at Sun Mar 03 08:20:09 EST 2024

STATUS

proposed

approved

#26 by Michel Marcus at Sun Mar 03 08:16:21 EST 2024

STATUS

editing

proposed

#25 by Michel Marcus at Sun Mar 03 08:16:17 EST 2024

COMMENTS

From R. J. Mathar, 07 Apr 07 2017: (Start)

STATUS

approved

editing

#24 by Susanna Cuyler at Sat Mar 14 18:53:49 EDT 2020

STATUS

proposed

approved

#23 by Andrew Howroyd at Sat Mar 14 12:44:57 EDT 2020

STATUS

editing

proposed

#22 by Andrew Howroyd at Mon Mar 09 19:13:52 EDT 2020

LINKS

Andrew Howroyd, <a href="/A139670/b139670.txt">Table of n, a(n) for n = 4..30</a>

CROSSREFS

Column k=4 of A333157 and row 4 of A188448.

#21 by Andrew Howroyd at Mon Mar 09 16:17:54 EDT 2020

DATA

1, 26, 820, 35150, 1944530, 133948836, 11234051976, 1127512146540, 133475706272700, 18406586045919060, 2925154024273348296, 530686776655470875076, 109004840145995702773410, 25164525076896596670014400, 6486836210471246515195539840, 1856264107759263993451053077856

KEYWORD

nonn,more

nonn

EXTENSIONS

Terms a(13) and beyond from Andrew Howroyd, Mar 09 2020

STATUS

approved

editing

#20 by Joerg Arndt at Mon Jul 24 01:54:47 EDT 2017

STATUS

reviewed

approved

#19 by Michel Marcus at Sun Jul 23 13:28:05 EDT 2017

STATUS

proposed

reviewed

#18 by Joerg Arndt at Sun Jul 23 12:22:27 EDT 2017

STATUS

editing

proposed