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A224600 Number of (n+2)X4 0..2 matrices with each 3X3 subblock idempotent 1
178, 272, 371, 449, 630, 894, 1221, 1707, 2440, 3476, 4979, 7189, 10414, 15114, 22001, 32083, 46840, 68452, 100119, 146509, 214482, 314086, 460049, 673947, 987416, 1446808, 2120063, 3106745, 4552782, 6672030, 9777921, 14329803, 21000892 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A224606

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) -2*a(n-2) -a(n-3) +a(n-4) -a(n-5) +2*a(n-6) -a(n-7) for n>9.

Empirical g.f.: 178*x + 272*x^2 -x^3*(-371 +664*x -25*x^2 -273*x^3 +123*x^4 -384*x^5 +268*x^6) / ( (1+x)*(x^3+x-1)*(x-1)^3 ). - R. J. Mathar, Aug 22 2016

EXAMPLE

Some solutions for n=3

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

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

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

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

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

CROSSREFS

Sequence in context: A046436 A114081 A217037 * A279093 A297400 A297600

Adjacent sequences:  A224597 A224598 A224599 * A224601 A224602 A224603

KEYWORD

nonn

AUTHOR

R. H. Hardin Apr 11 2013

STATUS

approved

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Last modified January 25 21:23 EST 2021. Contains 340427 sequences. (Running on oeis4.)