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A299590 Number of n X 3 0..1 arrays with every element unequal to 0, 1 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. 1
3, 3, 5, 11, 19, 35, 65, 120, 220, 404, 744, 1369, 2517, 4629, 8515, 15662, 28806, 52982, 97450, 179239, 329671, 606359, 1115269, 2051300, 3772928, 6939496, 12763724, 23476149, 43179369, 79419241, 146074759, 268673370, 494167370, 908915498 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A299595.

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) +2*a(n-3) +a(n-4) +a(n-5) for n>8.

Empirical g.f.: x*(3 + 2*x^2 - x^4 + x^7) / ((1 + x^2)*(1 - x - x^2 - x^3)). - Colin Barker, Feb 15 2018

EXAMPLE

Some solutions for n=5:

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

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

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

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

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

CROSSREFS

Cf. A299595.

Sequence in context: A301500 A084656 A073749 * A250396 A201866 A191632

Adjacent sequences:  A299587 A299588 A299589 * A299591 A299592 A299593

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 13 2018

STATUS

approved

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Last modified August 10 13:12 EDT 2022. Contains 356039 sequences. (Running on oeis4.)