A224565 - OEIS

A224565

Number of (n+3) X 8 0..1 matrices with each 4 X 4 subblock idempotent.

990, 611, 728, 861, 974, 1233, 1614, 2099, 2665, 3459, 4600, 6193, 8316, 11198, 15183, 20724, 28348, 38815, 53225, 73135, 100625, 138539, 190817, 262960, 362545, 499997, 689677, 951451, 1312758, 1811466, 2499800, 3449855, 4761161, 6571120, 9069355

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OFFSET

1,1

COMMENTS

Column 5 of A224568.

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) - 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*(990 - 2359*x + 875*x^2 + 1879*x^3 - 2891*x^4 + 2015*x^5 + 506*x^6 - 1569*x^7 + 517*x^8 + 35*x^9) / ((1 - x)^3*(1 + x)*(1 - x - x^4)). - Colin Barker, Sep 01 2018

EXAMPLE

Some solutions for n=3:

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

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

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

CROSSREFS

Cf. A224568.

Sequence in context: A217719 A223156 A087702 * A341604 A295768 A255917

Adjacent sequences: A224562 A224563 A224564 * A224566 A224567 A224568

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 10 2013

STATUS

approved