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A280174 Number of n X 2 0..1 arrays with no element unequal to a strict majority of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards. 1
1, 2, 12, 41, 103, 263, 656, 1618, 3931, 9459, 22557, 53395, 125594, 293796, 683972, 1585588, 3661900, 8428646, 19341455, 44261305, 101034472, 230100558, 522936849, 1186138105, 2685582035, 6070360107, 13699764020, 30873005212, 69478759648 (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) = 4*a(n-1) - 11*a(n-3) - 4*a(n-4) + 15*a(n-5) + 14*a(n-6) - 2*a(n-7) - 9*a(n-8) - 5*a(n-9) - a(n-10) for n>14.

Empirical g.f.: x*(1 - 2*x + 4*x^2 + 4*x^3 - 35*x^4 - 24*x^5 + 59*x^6 + 85*x^7 - 6*x^8 - 69*x^9 - 43*x^10 - 5*x^11 + 3*x^12 + x^13) / ((1 - x)*(1 - x - 2*x^2 - x^3)^3). - Colin Barker, Feb 13 2019

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 2 of A280180.

Sequence in context: A188572 A098519 A127725 * A185619 A048014 A094702

Adjacent sequences:  A280171 A280172 A280173 * A280175 A280176 A280177

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 28 2016

STATUS

approved

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Last modified August 11 12:12 EDT 2022. Contains 356065 sequences. (Running on oeis4.)