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A224605 Number of (n+2) X 9 0..2 matrices with each 3 X 3 subblock idempotent. 1
1694, 1221, 1455, 1657, 2091, 2656, 3308, 4272, 5672, 7588, 10325, 14312, 20058, 28377, 40512, 58215, 84052, 121832, 177116, 258031, 376513, 550059, 804293, 1176775, 1722562, 2522335, 3694335, 5411860, 7928889, 11617642, 17023637 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 7 of A224606.

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) - 6*a(n-2) + 5*a(n-3) - 4*a(n-4) + 3*a(n-5) - a(n-6) for n>8.

Empirical g.f.: x*(1694 - 5555*x + 6735*x^2 - 5307*x^3 + 4864*x^4 - 3239*x^5 + 796*x^6 + 5*x^7) / ((1 - x)^3*(1 - x - x^3)). - Colin Barker, Sep 02 2018

EXAMPLE

Some solutions for n=3:

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

..0..0..0..0..0..0..0..0..0....1..0..0..0..0..0..0..0..2

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

..0..0..0..0..0..0..0..0..0....2..0..0..0..0..0..0..0..1

..0..0..0..0..0..1..1..1..1....2..0..0..0..0..0..0..0..1

CROSSREFS

Cf. A224606.

Sequence in context: A089674 A252429 A126720 * A252570 A235182 A237170

Adjacent sequences:  A224602 A224603 A224604 * A224606 A224607 A224608

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 11 2013

STATUS

approved

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Last modified May 21 15:32 EDT 2019. Contains 323444 sequences. (Running on oeis4.)