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A301487
Number of nX4 0..1 arrays with every element equal to 0, 1, 2, 4, 5 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
1
8, 50, 148, 599, 2354, 9415, 38558, 158994, 657238, 2721509, 11274883, 46736042, 193836729, 804279754, 3338261393, 13859019181, 57545314726, 238962743161, 992381007429, 4121406272689, 17116902820124, 71090859437426
OFFSET
1,1
COMMENTS
Column 4 of A301491.
FORMULA
Empirical recurrence of order 89 (see link above)
EXAMPLE
Some solutions for n=5
..0..1..0..1. .0..0..1..1. .0..1..0..1. .0..0..1..0. .0..0..0..1
..0..1..0..1. .1..0..1..0. .1..1..1..0. .0..1..1..1. .0..0..1..0
..0..1..0..1. .1..1..1..1. .0..1..1..1. .1..1..0..0. .0..0..0..0
..0..1..0..1. .0..1..0..1. .0..1..0..1. .0..1..1..1. .0..0..0..0
..0..1..0..0. .0..0..1..0. .0..0..1..0. .0..0..0..0. .0..1..1..1
CROSSREFS
Cf. A301491.
Sequence in context: A300494 A300933 A300877 * A299686 A133426 A212063
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 22 2018
STATUS
approved