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A302636 Number of 3Xn 0..1 arrays with every element equal to 0, 1, 3 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. 1
4, 6, 8, 14, 25, 47, 83, 150, 269, 488, 876, 1581, 2845, 5133, 9242, 16661, 30012, 54094, 97457, 175631, 316451, 570258, 1027529, 1851592, 3336392, 6012049, 10833241, 19520945, 35175378, 63384029, 114213840, 205806518, 370850169, 668249367 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A302635.

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) +a(n-2) +2*a(n-4) -a(n-5) for n>7

EXAMPLE

Some solutions for n=5

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

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

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

CROSSREFS

Cf. A302635.

Sequence in context: A246324 A280227 A181978 * A000937 A138001 A239659

Adjacent sequences:  A302633 A302634 A302635 * A302637 A302638 A302639

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 10 2018

STATUS

approved

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Last modified April 6 08:53 EDT 2020. Contains 333268 sequences. (Running on oeis4.)