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A224556 Number of (n+2) X 7 0..1 matrices with each 3 X 3 subblock idempotent. 1
263, 246, 320, 395, 540, 740, 988, 1351, 1881, 2623, 3689, 5243, 7494, 10763, 15535, 22504, 32685, 47578, 69377, 101291, 148029, 216494, 316798, 463762, 679110, 994678, 1457123, 2134826, 3128004, 4583531, 6716662, 9842869, 14424498 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 5 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*(263 - 806*x + 914*x^2 - 724*x^3 + 702*x^4 - 455*x^5 + 98*x^6 + 5*x^7) / ((1 - x)^3*(1 - x - x^3)). - Colin Barker, Aug 31 2018

EXAMPLE

Some solutions for n=3:

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

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

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

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

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

CROSSREFS

Cf. A224559.

Sequence in context: A264972 A241877 A270752 * A052033 A105008 A345577

Adjacent sequences:  A224553 A224554 A224555 * A224557 A224558 A224559

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 10 2013

STATUS

approved

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Last modified October 16 06:47 EDT 2021. Contains 348040 sequences. (Running on oeis4.)