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A224687 Number of (n+4) X 9 0..1 matrices with each 5 X 5 subblock idempotent. 1
4405, 1938, 2136, 2429, 2700, 2926, 3540, 4514, 5773, 7247, 8885, 11074, 14173, 18466, 24167, 31439, 40832, 53255, 69901, 92177, 121653, 160449, 211594, 279310, 369226, 488541, 646574, 855673, 1132408, 1498978, 1984781, 2628534, 3481302 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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) + 4*a(n-3) - a(n-4) + a(n-5) - 3*a(n-6) + 3*a(n-7) - a(n-8) for n>12.

Empirical g.f.: x*(4405 - 15682*x + 20814*x^2 - 12107*x^3 + 2453*x^4 - 4311*x^5 + 11733*x^6 - 9998*x^7 + 2523*x^8 + 122*x^9 + 42*x^10 + 5*x^11) / ((1 - x)^3*(1 - x + x^2)*(1 - x^2 - x^3)). - Colin Barker, Sep 03 2018

EXAMPLE

Some solutions for n=2:

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

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

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

..0..0..0..0..0..0..0..0..0....0..0..0..0..0..0..0..0..0

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

CROSSREFS

Column 5 of A224690.

Sequence in context: A345184 A152931 A045013 * A050664 A303095 A039818

Adjacent sequences:  A224684 A224685 A224686 * A224688 A224689 A224690

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 15 2013

STATUS

approved

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Last modified September 18 12:35 EDT 2021. Contains 347527 sequences. (Running on oeis4.)