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A280438
Number of n X 6 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
10, 68, 136, 232, 360, 548, 834, 1284, 2008, 3188, 5128, 8332, 13638, 22436, 37032, 61248, 101416, 168020, 278410, 461284, 764088, 1265228, 2094216, 3464892, 5730190, 9472388, 15651784, 25851544, 42680808, 70438148, 116203218, 191632452
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.: 2*x*(5 + 14*x - 48*x^2 - 10*x^3 + 36*x^4 + 18*x^5 + 6*x^6) / ((1 - x)^2*(1 - x - x^2)^2). - Colin Barker, Feb 13 2019
EXAMPLE
Some solutions for n=4:
..0..1..0..1..0..1. .0..1..0..0..1..1. .0..0..1..1..0..0. .0..0..1..0..1..0
..0..0..1..0..1..0. .1..0..1..1..0..1. .0..1..0..0..1..1. .1..1..0..1..0..1
..0..1..0..1..0..1. .0..1..0..0..1..0. .1..0..1..1..0..0. .0..0..1..0..1..0
..1..0..1..0..1..0. .1..0..1..1..0..1. .0..1..0..0..1..1. .1..1..0..1..1..1
CROSSREFS
Column 6 of A280440.
Sequence in context: A197783 A197751 A144052 * A192021 A026984 A104598
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 03 2017
STATUS
approved