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A301886 Number of 3Xn 0..1 arrays with every element equal to 0, 1 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero. 1
4, 13, 29, 58, 125, 331, 823, 2086, 5269, 13305, 33569, 85096, 215567, 546143, 1383865, 3506890, 8886317, 22519583, 57069217, 144624880, 366509807, 928817445, 2353826833, 5965120912, 15116952851, 38309747249, 97085489873, 246036440460 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A301884.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) +3*a(n-3) +a(n-4) -a(n-5) +10*a(n-6) -13*a(n-7) -a(n-8) -19*a(n-9) -10*a(n-10) -8*a(n-11) -30*a(n-12) +8*a(n-13) -10*a(n-14) +19*a(n-15) -a(n-16) +13*a(n-17) +10*a(n-18) +a(n-19) +a(n-20) -3*a(n-21) -2*a(n-23) -a(n-24) for n>25

EXAMPLE

Some solutions for n=5

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

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

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

CROSSREFS

Cf. A301884.

Sequence in context: A168559 A212247 A213801 * A015634 A266891 A241399

Adjacent sequences:  A301883 A301884 A301885 * A301887 A301888 A301889

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 28 2018

STATUS

approved

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Last modified July 25 15:22 EDT 2021. Contains 346290 sequences. (Running on oeis4.)