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A302311 Number of 3Xn 0..1 arrays with every element equal to 0, 1, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. 1
4, 6, 13, 26, 48, 121, 275, 600, 1296, 2998, 6731, 15022, 33412, 75480, 169232, 379265, 848913, 1907065, 4276079, 9589159, 21494910, 48224727, 108142434, 242526545, 543834226, 1219737296, 2735350513, 6134430103, 13756843652, 30852213480 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A302309.

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) +3*a(n-2) -a(n-3) +8*a(n-4) -7*a(n-5) -22*a(n-6) +9*a(n-7) -14*a(n-8) +10*a(n-9) +39*a(n-10) -19*a(n-11) +6*a(n-12) -18*a(n-14) +9*a(n-15) for n>16

EXAMPLE

Some solutions for n=5

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

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

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

CROSSREFS

Cf. A302309.

Sequence in context: A262194 A136391 A105205 * A160805 A246424 A012776

Adjacent sequences:  A302308 A302309 A302310 * A302312 A302313 A302314

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 05 2018

STATUS

approved

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Last modified July 4 20:49 EDT 2022. Contains 355086 sequences. (Running on oeis4.)