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A300374
Number of nX2 0..1 arrays with every element equal to 0, 2 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
4
1, 3, 2, 10, 13, 42, 74, 188, 387, 885, 1937, 4275, 9526, 20871, 46566, 102205, 227355, 500590, 1110398, 2450549, 5426150, 11990298, 26526428, 58649475, 129706253, 286835657, 634286359, 1402736818, 3101877239, 6859804246, 15169348965
OFFSET
1,2
COMMENTS
Column 2 of A300380.
LINKS
FORMULA
Empirical: a(n) = 4*a(n-2) +2*a(n-3) +a(n-5) -3*a(n-6) +a(n-7)
EXAMPLE
Some solutions for n=5
..0..1. .0..1. .0..0. .0..0. .0..0. .0..0. .0..1. .0..1. .0..0. .0..0
..1..1. .1..1. .0..1. .0..1. .0..1. .0..0. .1..1. .1..1. .0..1. .0..1
..1..0. .0..1. .1..1. .1..1. .1..1. .1..0. .1..0. .0..0. .1..1. .0..0
..0..0. .1..1. .0..0. .0..0. .1..0. .0..0. .1..1. .0..1. .0..1. .1..0
..0..1. .1..0. .0..0. .0..1. .0..0. .0..1. .1..0. .1..1. .1..1. .0..0
CROSSREFS
Cf. A300380.
Sequence in context: A095675 A340806 A226442 * A256063 A006743 A091811
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 04 2018
STATUS
approved