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A224555 Number of (n+2) X 6 0..1 matrices with each 3 X 3 subblock idempotent. 1
172, 174, 230, 286, 395, 551, 749, 1041, 1473, 2086, 2973, 4273, 6166, 8925, 12962, 18869, 27511, 40165, 58700, 85850, 125626, 183908, 269310, 394457, 577854, 846620, 1240499, 1817740, 2663711, 3903524, 5720540, 8383488, 12286209, 18005905 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 of A224559.

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*(172 - 514*x + 566*x^2 - 450*x^3 + 449*x^4 - 283*x^5 + 55*x^6 + 4*x^7) / ((1 - x)^3*(1 - x - x^3)). - Colin Barker, Aug 31 2018

EXAMPLE

Some solutions for n=3:

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

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

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

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

CROSSREFS

Cf. A224559.

Sequence in context: A252132 A252131 A223823 * A146339 A067356 A230371

Adjacent sequences:  A224552 A224553 A224554 * A224556 A224557 A224558

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 10 2013

STATUS

approved

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Last modified October 23 17:32 EDT 2019. Contains 328373 sequences. (Running on oeis4.)