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A300540
Number of n X n 0..1 arrays with every element equal to 1, 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
0
0, 3, 71, 5232, 1338834, 1170734982, 3494400946777, 35649209732530747, 1243019949106504713542, 148132659013363179054567570, 60334773902381858388914690621425
OFFSET
1,2
COMMENTS
Diagonal of A300546.
EXAMPLE
Some solutions for n=5
..0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0
..0..0..0..1..1. .0..0..1..1..0. .1..0..0..1..1. .0..1..1..1..1
..1..1..1..1..1. .1..1..0..0..1. .1..1..0..0..0. .1..0..1..0..1
..0..0..0..0..1. .1..0..0..1..1. .1..0..1..0..0. .0..1..0..0..1
..0..1..1..1..1. .0..1..1..0..0. .1..0..1..1..0. .1..0..0..0..0
CROSSREFS
Cf. A300546.
Sequence in context: A272657 A226709 A226844 * A334124 A336441 A073589
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 08 2018
STATUS
approved