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A297433 Number of 3Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 2 neighboring 1s. 1
1, 3, 14, 26, 43, 109, 301, 649, 1332, 3124, 7545, 16925, 37301, 85611, 198538, 450262, 1014883, 2315761, 5303161, 12062833, 27380904, 62381096, 142295761, 323928537, 736878729, 1678132851, 3823284742, 8705263890, 19816325051, 45124192277 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row 3 of A297431.

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) +3*a(n-3) +8*a(n-4) +a(n-5) -a(n-6).

Empirical: G.f.: -x*(-1-2*x-11*x^2-9*x^3+x^5)/(1-x-3*x^3-8*x^4-x^5+x^6) . - R. J. Mathar, Feb 13 2018

EXAMPLE

Some solutions for n=5

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

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

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

CROSSREFS

Cf. A297431.

Sequence in context: A017425 A302758 A063098 * A032300 A032212 A032137

Adjacent sequences:  A297430 A297431 A297432 * A297434 A297435 A297436

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 30 2017

STATUS

approved

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Last modified April 23 05:42 EDT 2021. Contains 343199 sequences. (Running on oeis4.)