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A281049 Number of n X n 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards. 0
0, 1, 68, 1022, 7803, 46610, 221212, 926077, 3549039, 12749511, 43675963, 144504080, 466130380 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Diagonal of A281056.

LINKS

Table of n, a(n) for n=1..13.

EXAMPLE

Some solutions for n=4

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

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

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

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

CROSSREFS

Cf. A281056.

Sequence in context: A250338 A223374 A254645 * A264316 A251939 A163728

Adjacent sequences:  A281046 A281047 A281048 * A281050 A281051 A281052

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 13 2017

STATUS

approved

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Last modified January 15 18:43 EST 2021. Contains 340188 sequences. (Running on oeis4.)