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A296033 Number of n X 2 0..1 arrays with each 1 adjacent to 2 or 4 king-move neighboring 1s. 1
1, 5, 11, 21, 55, 125, 271, 645, 1479, 3325, 7695, 17653, 40183, 92269, 211487, 483365, 1107591, 2537245, 5806511, 13298005, 30454935, 69724365, 159661375, 365617029, 837155239, 1916943229, 4389542863, 10051119797, 23015247287, 52701125421 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) + 6*a(n-3) + 4*a(n-5).

Empirical g.f.: x*(1 + 4*x + 6*x^2 + 4*x^3 + 4*x^4) / (1 - x - 6*x^3 - 4*x^5). - Colin Barker, Feb 22 2019

EXAMPLE

Some solutions for n=5:

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

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

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

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

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

CROSSREFS

Column 2 of A296039.

Sequence in context: A168642 A234597 A261982 * A296968 A184552 A069097

Adjacent sequences:  A296030 A296031 A296032 * A296034 A296035 A296036

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 03 2017

STATUS

approved

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Last modified June 6 18:59 EDT 2020. Contains 334832 sequences. (Running on oeis4.)