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A301952 Number of 3Xn 0..1 arrays with every element equal to 1, 2 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero. 1
0, 5, 20, 123, 680, 4070, 23565, 138014, 805249, 4704141, 27469522, 160428571, 936897912, 5471539885, 31953953498, 186612354231, 1089822896327, 6364606387628, 37169536347339, 217071469820879, 1267705419106309 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row 3 of A301951.

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) +12*a(n-2) -5*a(n-3) -14*a(n-4) +14*a(n-6) +4*a(n-7) -3*a(n-8) -5*a(n-9) +a(n-10) for n>12

EXAMPLE

Some solutions for n=5

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

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

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

CROSSREFS

Cf. A301951.

Sequence in context: A054720 A208941 A209069 * A110373 A081067 A318250

Adjacent sequences:  A301949 A301950 A301951 * A301953 A301954 A301955

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 29 2018

STATUS

approved

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Last modified October 20 08:20 EDT 2021. Contains 348099 sequences. (Running on oeis4.)