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A269882 Number of n X 2 0..5 arrays with some element plus some horizontally, diagonally, antidiagonally or vertically adjacent neighbor totalling five exactly once. 1
6, 432, 11280, 250992, 5125008, 99482544, 1867222224, 34216907760, 615877284624, 10931855797296, 191890772032848, 3337772595455088, 57618604390530960, 988280162421210288, 16858064726292134352, 286196732519053403376 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 30*a(n-1) - 197*a(n-2) - 420*a(n-3) - 196*a(n-4) for n>5.

Empirical g.f.: 6*x*(1 - x)^2*(1 + 44*x + 4*x^2) / (1 - 15*x - 14*x^2)^2. - Colin Barker, Jan 29 2019

EXAMPLE

Some solutions for n=3:

..5..5. .1..1. .0..4. .1..2. .4..3. .3..3. .2..4. .4..2. .0..2. .1..4

..5..3. .3..2. .4..0. .2..1. .4..3. .1..0. .1..5. .4..5. .1..0. .3..3

..1..2. .4..5. .5..4. .3..0. .0..1. .2..3. .1..1. .3..2. .1..5. .3..4

CROSSREFS

Column 2 of A269888.

Sequence in context: A000410 A275686 A173760 * A262013 A028665 A231316

Adjacent sequences:  A269879 A269880 A269881 * A269883 A269884 A269885

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 06 2016

STATUS

approved

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Last modified August 3 20:08 EDT 2020. Contains 336201 sequences. (Running on oeis4.)