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A302076
Number of nX3 0..1 arrays with every element equal to 0, 1, 3 or 4 horizontally or antidiagonally adjacent elements, with upper left element zero.
1
3, 10, 33, 115, 386, 1323, 4485, 15290, 51977, 176947, 601946, 2048483, 6969893, 23717058, 80700241, 274599219, 934369138, 3179364635, 10818345477, 36811374474, 125257251353, 426210254579, 1450256511946, 4934757299411
OFFSET
1,1
COMMENTS
Column 3 of A302081.
LINKS
FORMULA
Empirical: a(n) = a(n-1) +7*a(n-2) +4*a(n-3)
EXAMPLE
Some solutions for n=5
..0..0..1. .0..1..1. .0..1..1. .0..1..0. .0..0..0. .0..0..0. .0..0..1
..1..0..0. .0..0..1. .0..0..0. .0..1..0. .0..1..0. .0..1..0. .1..1..1
..1..1..0. .1..0..1. .0..1..1. .0..1..1. .0..1..1. .1..0..1. .1..0..1
..0..1..0. .0..1..0. .0..0..1. .0..0..1. .0..0..1. .1..0..1. .1..1..1
..0..0..0. .0..0..0. .1..0..1. .1..0..1. .1..0..0. .1..0..1. .1..0..0
CROSSREFS
Cf. A302081.
Sequence in context: A001558 A304824 A111639 * A149029 A149030 A024426
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 31 2018
STATUS
approved