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A297638 Number of 2Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 0, 2 or 3 neighboring 1s. 1
4, 8, 29, 69, 200, 552, 1641, 4685, 13716, 40248, 119365, 353541, 1051472, 3133592, 9358769, 27971501, 83684604, 250541896, 750515501, 2248981061, 6741211928, 20210867784, 60604323641, 181749073613, 545104106532, 1634992796824 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 2 of A297637.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 3*a(n-1) +a(n-2) -a(n-3) +6*a(n-4) -28*a(n-5) -24*a(n-6)

EXAMPLE

Some solutions for n=7

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

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

CROSSREFS

Cf. A297637.

Sequence in context: A300461 A280085 A322784 * A256456 A270522 A317583

Adjacent sequences:  A297635 A297636 A297637 * A297639 A297640 A297641

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 02 2018

STATUS

approved

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Last modified August 10 03:47 EDT 2020. Contains 336368 sequences. (Running on oeis4.)