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A296572 Number of n X 2 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 0, 1 or 3 neighboring 1s. 1
4, 11, 31, 90, 254, 728, 2078, 5931, 16941, 48360, 138093, 394288, 1125795, 3214477, 9178177, 26206271, 74826094, 213649101, 610027119, 1741795342, 4973305753, 14200157940, 40545363081, 115768182159, 330550053876, 943811471644 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) + 4*a(n-2) + 3*a(n-3) + a(n-4) + 4*a(n-5) - a(n-6) - 6*a(n-7) - a(n-8) + a(n-9).

Empirical g.f.: x*(4 + 7*x + 4*x^2 + 3*x^3 + 3*x^4 - 6*x^5 - 7*x^6 + x^8) / (1 - x - 4*x^2 - 3*x^3 - x^4 - 4*x^5 + x^6 + 6*x^7 + x^8 - x^9). - Colin Barker, Feb 23 2019

EXAMPLE

Some solutions for n=5:

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

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

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

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

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

CROSSREFS

Column 2 of A296578.

Sequence in context: A077995 A276293 A282856 * A176573 A076730 A084757

Adjacent sequences:  A296569 A296570 A296571 * A296573 A296574 A296575

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 15 2017

STATUS

approved

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Last modified August 25 09:11 EDT 2019. Contains 326323 sequences. (Running on oeis4.)