

A296329


Number of n X 2 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 0 or 2 neighboring 1s.


2



3, 8, 19, 47, 116, 286, 705, 1738, 4285, 10564, 26044, 64208, 158296, 390257, 962125, 2371987, 5847808, 14416967, 35543051, 87626508, 216031114, 532595025, 1313039846, 3237119305, 7980672808, 19675252120, 48506630368, 119586431488
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OFFSET

1,1


COMMENTS



LINKS



FORMULA

Empirical: a(n) = a(n1) + 2*a(n2) + 3*a(n3) + 2*a(n4) + a(n5).
Empirical g.f.: x*(3 + 5*x + 5*x^2 + 3*x^3 + x^4) / (1  x  2*x^2  3*x^3  2*x^4  x^5).  Colin Barker, Mar 22 2018


EXAMPLE

Some solutions for n=5:
..1..0. .0..0. .1..0. .0..0. .1..0. .0..0. .1..0. .1..0. .0..0. .1..0
..0..0. .1..0. .0..0. .0..0. .0..1. .0..0. .0..0. .0..1. .0..1. .0..1
..0..0. .0..0. .0..0. .0..1. .0..0. .1..1. .1..0. .0..0. .0..0. .0..0
..0..1. .0..0. .0..0. .0..0. .0..1. .1..0. .0..0. .0..0. .0..0. .0..1
..1..1. .1..0. .0..1. .0..1. .0..0. .0..1. .0..0. .1..0. .1..0. .1..1


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



