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A302618 Number of nX3 0..1 arrays with every element equal to 0, 1, 2 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. 1
4, 17, 25, 71, 191, 498, 1321, 3505, 9240, 24460, 64759, 171268, 453200, 1199361, 3173346, 8396961, 22219739, 58794851, 155576745, 411673594, 1089327367, 2882467725, 7627305260, 20182608868, 53405199549, 141315536296, 373935069260 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A302623.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) +a(n-2) +4*a(n-3) -4*a(n-4) -4*a(n-5) +a(n-6) -4*a(n-7) -4*a(n-9) for n>11

EXAMPLE

Some solutions for n=5

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

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

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

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

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

CROSSREFS

Cf. A302623.

Sequence in context: A009226 A273022 A273119 * A171227 A061387 A335593

Adjacent sequences:  A302615 A302616 A302617 * A302619 A302620 A302621

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 10 2018

STATUS

approved

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Last modified October 25 01:40 EDT 2021. Contains 348233 sequences. (Running on oeis4.)