The On-Line Encyclopedia of Integer Sequences (OEIS)

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A210896

Number of n X n 0..2 symmetric matrices with every element equal to zero or one horizontal and vertical neighbors, and new values 0..2 introduced in lower triangle row major order
(history; published version)

#6 by Charles R Greathouse IV at Fri Dec 18 18:18:05 EST 2015

NAME

Number of nXn n X n 0..2 symmetric matrices with every element equal to zero or one horizontal and vertical neighbors, and new values 0..2 introduced in lower triangle row major order

Discussion

Fri Dec 18

18:18

OEIS Server: https://oeis.org/edit/global/2478

#5 by Russ Cox at Sat Mar 31 12:37:34 EDT 2012

AUTHOR

_R. H. Hardin (rhhardin(AT)att.net) _ Mar 29 2012

Discussion

Sat Mar 31

12:37

OEIS Server: https://oeis.org/edit/global/875

#4 by Ron Hardin at Thu Mar 29 08:32:59 EDT 2012

STATUS

editing

approved

#3 by Ron Hardin at Thu Mar 29 08:32:55 EDT 2012

NAME

allocated for Ron HardinNumber of nXn 0..2 symmetric matrices with every element equal to zero or one horizontal and vertical neighbors, and new values 0..2 introduced in lower triangle row major order

DATA

1, 2, 20, 400, 16716, 1444348, 258951340, 96266852004, 74214689922928, 118642250445743920, 393305989512539553728, 2703723885515478100466476, 38542035415959856159523945096

OFFSET

1,2

EXAMPLE

Some solutions for n=3

..0..1..0....0..1..1....0..1..0....0..1..0....0..1..0....0..1..0....0..1..0

..1..2..0....1..0..2....1..0..2....1..2..1....1..0..1....1..0..2....1..2..0

..0..0..1....1..2..0....0..2..1....0..1..0....0..1..0....0..2..0....0..0..2

KEYWORD

allocated

nonn

AUTHOR

R. H. Hardin (rhhardin(AT)att.net) Mar 29 2012

STATUS

approved

editing

#2 by Ron Hardin at Thu Mar 29 08:23:55 EDT 2012

KEYWORD

allocating

allocated

#1 by Ron Hardin at Thu Mar 29 08:23:55 EDT 2012

NAME

allocated for Ron Hardin

KEYWORD

allocating

STATUS

approved