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A303406 Number of nX3 0..1 arrays with every element equal to 1, 2, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. 1
1, 7, 28, 119, 541, 2327, 10384, 47491, 208616, 938105, 4229023, 18855226, 84609455, 379973132, 1700940358, 7627893865, 34215621269, 153337948168, 687522535009, 3082887354405, 13820286385598, 61963243406462, 277818915171978 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A303410.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) +7*a(n-2) +35*a(n-3) -36*a(n-4) -151*a(n-5) -97*a(n-6) +34*a(n-7) +258*a(n-8) -724*a(n-9) +256*a(n-10) +1584*a(n-11) -240*a(n-12) -512*a(n-13) -304*a(n-14) +1728*a(n-15) -1344*a(n-16) -1792*a(n-17) +1024*a(n-18)

EXAMPLE

Some solutions for n=5

..0..1..1. .0..1..0. .0..1..0. .0..0..0. .0..1..0. .0..0..1. .0..0..0

..1..0..0. .0..0..1. .1..0..1. .0..1..0. .0..0..1. .0..1..1. .1..0..1

..1..0..1. .0..0..0. .0..1..0. .1..0..0. .1..0..0. .0..1..0. .0..1..0

..1..1..1. .1..1..0. .1..0..1. .1..1..0. .1..1..1. .0..0..0. .1..0..1

..0..0..0. .0..0..1. .1..1..1. .1..0..1. .0..0..1. .0..0..0. .0..0..0

CROSSREFS

Cf. A303410.

Sequence in context: A037702 A302523 A290913 * A054626 A220361 A219737

Adjacent sequences:  A303403 A303404 A303405 * A303407 A303408 A303409

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 23 2018

STATUS

approved

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Last modified September 23 12:20 EDT 2021. Contains 347617 sequences. (Running on oeis4.)