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A303620 Number of nX4 0..1 arrays with every element equal to 0, 2, 3, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. 1
1, 20, 68, 325, 1870, 10741, 62207, 363485, 2135551, 12586013, 74323727, 439462339, 2600501501, 15395919313, 91177465195, 540072985865, 3199404347759, 18954749501705, 112301887289875, 665378205627245, 3942374534440139 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 4 of A303624.

LINKS

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

FORMULA

Empirical: a(n) = 9*a(n-1) -19*a(n-2) +19*a(n-3) -91*a(n-4) +33*a(n-5) -46*a(n-6) +295*a(n-7) +125*a(n-8) +527*a(n-9) -181*a(n-10) -44*a(n-11) -219*a(n-12) -360*a(n-13) +52*a(n-14) -131*a(n-15) -93*a(n-16) +23*a(n-17) +10*a(n-18) +70*a(n-19) +14*a(n-20) -16*a(n-21) +24*a(n-22) for n>24

EXAMPLE

Some solutions for n=5

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

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

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

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

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

CROSSREFS

Cf. A303624.

Sequence in context: A330931 A158444 A235281 * A221521 A145191 A044158

Adjacent sequences:  A303617 A303618 A303619 * A303621 A303622 A303623

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 27 2018

STATUS

approved

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Last modified October 28 13:26 EDT 2020. Contains 338055 sequences. (Running on oeis4.)