

A279460


Number of n X 2 0..1 arrays with no element equal to a strict majority of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.


1



0, 2, 6, 20, 66, 210, 658, 2036, 6236, 18928, 57032, 170790, 508748, 1508462, 4454576, 13107640, 38446722, 112448726, 328044512, 954771282, 2772970950, 8038036642, 23258558892, 67190053760, 193807573324, 558249440024, 1605908314802
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OFFSET

1,2


LINKS

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


FORMULA

Empirical: a(n) = 4*a(n1)  2*a(n2)  3*a(n4)  14*a(n5)  14*a(n6)  14*a(n7)  13*a(n8)  6*a(n9)  a(n10).
Empirical g.f.: 2*x^2*(1 + x)*(1  2*x + 2*x^2  3*x^3  x^4  x^5  x^6) / (1  2*x  x^2  2*x^3  3*x^4  x^5)^2.  Colin Barker, Feb 11 2019


EXAMPLE

Some solutions for n=4:
..0..1. .0..0. .0..1. .0..0. .0..1. .0..1. .0..1. .0..0. .0..0. .0..0
..0..0. .1..0. .0..0. .1..1. .0..1. .1..0. .1..0. .1..0. .1..0. .1..0
..1..0. .1..0. .0..1. .0..1. .0..1. .0..1. .1..0. .0..1. .0..1. .1..1
..1..1. .1..0. .1..0. .0..0. .0..0. .0..0. .1..1. .0..1. .1..0. .0..0


CROSSREFS

Column 2 of A279466.
Sequence in context: A148474 A156831 A027061 * A096487 A083323 A174846
Adjacent sequences: A279457 A279458 A279459 * A279461 A279462 A279463


KEYWORD

nonn


AUTHOR

R. H. Hardin, Dec 12 2016


STATUS

approved



