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A301994
Number of n X 3 0..1 arrays with every element equal to 1, 2 or 4 horizontally or antidiagonally adjacent elements, with upper left element zero.
1
1, 2, 5, 15, 48, 155, 499, 1602, 5137, 16467, 52784, 169199, 542375, 1738618, 5573261, 17865479, 57269040, 183579891, 588478091, 1886407378, 6047009817, 19384109803, 62137109808, 199184819687, 638500768991, 2046758546378, 6561026627701
OFFSET
1,2
COMMENTS
Column 3 of A301999.
LINKS
FORMULA
Empirical: a(n) = 5*a(n-1) - 7*a(n-2) + 4*a(n-3).
Empirical: partial sums of A049219. - Sean A. Irvine, Jul 13 2022
EXAMPLE
Some solutions for n=5:
0 0 0 0 0 1 0 0 1 0 0 1 0 0 1 0 0 0 0 0 1
1 1 0 1 1 0 1 1 1 0 1 1 1 1 1 1 1 0 1 1 1
1 0 0 0 0 0 1 0 0 0 0 1 1 1 1 0 0 0 1 0 0
1 1 0 0 1 1 1 1 0 0 1 0 1 0 0 0 1 0 1 1 1
1 0 0 1 0 0 1 0 0 1 0 0 0 1 1 1 0 0 0 0 0
CROSSREFS
Sequence in context: A149925 A149926 A321467 * A289589 A071739 A268407
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 30 2018
STATUS
approved