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A297434 Number of 4 X n 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 2 neighboring 1s. 1
1, 4, 22, 42, 105, 349, 1057, 2834, 8216, 24556, 71651, 207409, 608985, 1791636, 5251548, 15401954, 45271039, 133066199, 390990659, 1149260888, 3379206474, 9935995300, 29215600841, 85913309363, 252656693545, 743030170284 (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) = 3*a(n-1) + a(n-2) + a(n-4) - 33*a(n-5) - 7*a(n-6) + 21*a(n-7) + 3*a(n-8) + 2*a(n-9) + 3*a(n-10) + 5*a(n-11) - 2*a(n-12).

Empirical g.f.: x*(1 + x + 9*x^2 - 28*x^3 - 44*x^4 + 21*x^5 + 22*x^6 + 5*x^7 + 5*x^8 + 8*x^9 + 3*x^10 - 2*x^11) / ((1 + x)*(1 - 4*x + 3*x^2 - 3*x^3 + 2*x^4 + 31*x^5 - 24*x^6 + 3*x^7 - 6*x^8 + 4*x^9 - 7*x^10 + 2*x^11)). - Colin Barker, Feb 28 2019

EXAMPLE

Some solutions for n=5:

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

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

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

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

CROSSREFS

Row 4 of A297431.

Sequence in context: A031108 A163484 A326737 * A020173 A290709 A163433

Adjacent sequences:  A297431 A297432 A297433 * A297435 A297436 A297437

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 30 2017

STATUS

approved

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Last modified April 14 12:11 EDT 2021. Contains 342949 sequences. (Running on oeis4.)