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A224725 Number of (n+3) X 8 0..2 matrices with each 4 X 4 subblock idempotent. 1
4257, 3123, 3775, 4209, 4498, 5727, 7575, 9778, 12188, 15746, 21068, 28510, 38276, 51515, 69988, 95816, 131320, 179974, 247009, 339781, 467963, 644706, 888388, 1224747, 1689190, 2330279, 3214950, 4435881, 6121153, 8447413, 11658240 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..159

FORMULA

Empirical: a(n) = 3*a(n-1) - 2*a(n-2) - 2*a(n-3) + 4*a(n-4) - 3*a(n-5) + 2*a(n-7) - a(n-8) for n>10.

Empirical g.f.: x*(4257 - 9648*x + 2920*x^2 + 7644*x^3 - 11361*x^4 + 8480*x^5 + 2077*x^6 - 6522*x^7 + 2104*x^8 + 47*x^9) / ((1 - x)^3*(1 + x)*(1 - x - x^4)). - Colin Barker, Sep 04 2018

EXAMPLE

Some solutions for n=2:

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

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

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

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

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

CROSSREFS

Column 5 of A224728.

Sequence in context: A237805 A031985 A138399 * A252030 A023346 A231195

Adjacent sequences:  A224722 A224723 A224724 * A224726 A224727 A224728

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 16 2013

STATUS

approved

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Last modified December 5 12:04 EST 2021. Contains 349557 sequences. (Running on oeis4.)