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A303315 Number of 3Xn 0..1 arrays with every element equal to 0, 1, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. 1
4, 4, 12, 17, 24, 67, 158, 298, 595, 1337, 2863, 5840, 12231, 26168, 55140, 115193, 242621, 512713, 1078852, 2267487, 4776110, 10063518, 21181387, 44579665, 93874659, 197672892, 416137435, 876080072, 1844597384, 3883701257, 8176491213 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A303314.

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) +3*a(n-3) +4*a(n-4) for n>7

EXAMPLE

Some solutions for n=5

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

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

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

CROSSREFS

Cf. A303314.

Sequence in context: A136485 A157617 A053415 * A331606 A079902 A309128

Adjacent sequences:  A303312 A303313 A303314 * A303316 A303317 A303318

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 21 2018

STATUS

approved

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Last modified September 20 17:42 EDT 2021. Contains 347588 sequences. (Running on oeis4.)