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A280437
Number of n X 5 0..1 arrays with no element equal to more than one of its horizontal and vertical neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.
1
5, 38, 77, 138, 225, 360, 574, 920, 1487, 2422, 3971, 6542, 10814, 17914, 29713, 49314, 81861, 135876, 225470, 373996, 620083, 1027598, 1702087, 2817898, 4662910, 7712270, 12749909, 21068730, 34800297, 57457632, 94828606, 156445952
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) - 4*a(n-2) - 2*a(n-3) + 4*a(n-4) - a(n-6) for n>7.
Empirical g.f.: x*(5 + 18*x - 55*x^2 - 8*x^3 + 37*x^4 + 14*x^5 + 7*x^6) / ((1 - x)^2*(1 - x - x^2)^2). - Colin Barker, Feb 13 2019
EXAMPLE
Some solutions for n=4:
..0..1..1..0..0. .0..0..1..0..0. .0..1..0..1..1. .0..1..0..1..0
..1..0..0..1..0. .1..1..0..1..0. .1..0..1..0..0. .1..0..1..0..1
..0..1..1..0..1. .0..0..1..0..1. .1..0..0..1..1. .0..1..0..0..1
..1..0..0..1..0. .1..1..0..1..0. .0..1..1..0..0. .1..0..1..1..0
CROSSREFS
Column 5 of A280440.
Sequence in context: A061674 A247709 A097276 * A222646 A145156 A318102
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 03 2017
STATUS
approved