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A296110 Number of n X 3 0..1 arrays with each 1 adjacent to 3 or 4 king-move neighboring 1's. 1
1, 3, 6, 9, 26, 74, 163, 535, 1735, 4960, 15935, 51598, 159682, 507871, 1626269, 5134567, 16304686, 51939793, 164789906, 523362014, 1664172607, 5285951875, 16791701819, 53363480620, 169541243631, 538639046154, 1711496670766 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A296115.

LINKS

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

Robert Israel, Maple-assisted proof of formula

FORMULA

Empirical: a(n) = a(n-1) +3*a(n-2) +15*a(n-3) +2*a(n-4) -18*a(n-5) -36*a(n-6) -21*a(n-7) -25*a(n-8) +3*a(n-9) +11*a(n-10) +6*a(n-11).

Empirical formula verified by Robert Israel, Dec 04 2017 (see link).

EXAMPLE

Some solutions for n=7

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

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

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

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

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

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

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

CROSSREFS

Cf. A296115.

Sequence in context: A318032 A326160 A301536 * A019461 A223556 A067862

Adjacent sequences:  A296107 A296108 A296109 * A296111 A296112 A296113

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 04 2017

STATUS

approved

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Last modified June 6 16:34 EDT 2020. Contains 334828 sequences. (Running on oeis4.)