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A297954 Number of n X 3 0..1 arrays with every element equal to 1, 2, 4 or 5 king-move adjacent elements, with upper left element zero. 2
1, 7, 15, 25, 47, 109, 245, 545, 1253, 2859, 6557, 15131, 34879, 80643, 186663, 432253, 1002043, 2323805, 5391149, 12511905, 29043489, 67430735, 156577101, 363614071, 844480819, 1961394067, 4555748943, 10582066605, 24580613559, 57098398457 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A297959.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 2*a(n-1) + 2*a(n-2) + a(n-3) - 8*a(n-4) - 2*a(n-5) - 2*a(n-6) + 2*a(n-7) - a(n-8) + 2*a(n-9) + 3*a(n-11) + 2*a(n-12) for n>13.

Empirical g.f.: x*(1 - 2*x)*(1 + 7*x + 13*x^2 + 6*x^3 - 20*x^4 - 32*x^5 - 20*x^6 - 8*x^7 - 9*x^8 - 9*x^9 - 7*x^10 - 2*x^11) / ((1 - x)*(1 - x - 3*x^2 - 4*x^3 + 4*x^4 + 6*x^5 + 8*x^6 + 6*x^7 + 7*x^8 + 5*x^9 + 5*x^10+ 2*x^11)). - Colin Barker, Mar 22 2018

EXAMPLE

Some solutions for n=7:

..0..0..1. .0..1..0. .0..1..1. .0..1..1. .0..0..1. .0..1..1. .0..1..0

..1..1..1. .1..0..0. .0..1..0. .0..0..1. .1..0..1. .0..1..0. .1..0..1

..1..0..0. .1..0..0. .1..1..0. .1..1..1. .0..1..0. .1..0..1. .0..1..0

..1..1..0. .0..1..0. .1..1..1. .0..1..1. .0..1..1. .0..0..1. .0..1..1

..1..1..1. .1..0..0. .1..0..0. .0..1..0. .0..1..1. .0..0..1. .0..1..1

..1..0..0. .1..0..0. .1..1..1. .1..0..1. .0..1..0. .1..0..0. .0..1..0

..1..1..0. .0..1..0. .0..0..1. .0..1..0. .1..1..0. .0..1..1. .1..1..0

CROSSREFS

Cf. A297959.

Sequence in context: A323483 A236582 A268662 * A298577 A299569 A260558

Adjacent sequences:  A297951 A297952 A297953 * A297955 A297956 A297957

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 09 2018

STATUS

approved

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Last modified August 15 17:39 EDT 2022. Contains 356148 sequences. (Running on oeis4.)