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A181207 Number of n X 3 binary matrices with no two 1's adjacent diagonally or antidiagonally. 1
8, 25, 119, 484, 2117, 9025, 38936, 167281, 720083, 3097600, 13329209, 57350329, 246768392, 1061782225, 4568619071, 19657722436, 84582794333, 363940725625, 1565955363224, 6737954403049, 28991906279867, 124745667481600 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A181212.

LINKS

R. H. Hardin, Table of n, a(n) for n=1..400

FORMULA

Empirical: a(n) = 5*a(n-1) - 15*a(n-3) + 9*a(n-4).

Empirical g.f.: x*(8 - 15*x - 6*x^2 + 9*x^3) / ((1 - 5*x + 3*x^2)*(1 - 3*x^2)). - Colin Barker, Mar 26 2018

CROSSREFS

Cf. A181212.

Sequence in context: A335769 A139026 A135942 * A068315 A069586 A253237

Adjacent sequences:  A181204 A181205 A181206 * A181208 A181209 A181210

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 10 2010

STATUS

approved

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Last modified August 10 03:47 EDT 2020. Contains 336368 sequences. (Running on oeis4.)