

A281982


Number of n X 2 0..1 arrays with no element unequal to more than four of its kingmove neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.


1



0, 0, 2, 16, 88, 432, 2008, 8992, 39200, 167552, 705440, 2934784, 12091264, 49416448, 200598912, 809606656, 3251253760, 12999782400, 51779385856, 205542608896, 813446920192, 3210502631424, 12640023828480, 49653803819008
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OFFSET

1,3


LINKS

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


FORMULA

Empirical: a(n) = 8*a(n1)  20*a(n2) + 24*a(n3)  36*a(n4) + 16*a(n5)  16*a(n6).
Empirical g.f.: 2*x^3 / (1  4*x + 2*x^2  4*x^3)^2.  Colin Barker, Feb 20 2019


EXAMPLE

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


CROSSREFS

Column 2 of A281988.
Sequence in context: A220505 A069440 A000431 * A207595 A253487 A207019
Adjacent sequences: A281979 A281980 A281981 * A281983 A281984 A281985


KEYWORD

nonn


AUTHOR

R. H. Hardin, Feb 04 2017


STATUS

approved



