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A224546 Number of (n+1) X 5 0..1 matrices with each 2 X 2 subblock idempotent. 1
48, 86, 125, 196, 294, 448, 682, 1049, 1626, 2543, 4007, 6355, 10131, 16216, 26035, 41894, 67524, 108962, 175976, 284371, 459720, 743401, 1202365, 1944941, 3146409, 5090378, 8235737, 13324984, 21559506, 34883188, 56441302, 91323005, 147762726 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 of A224550.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 4*a(n-1) - 5*a(n-2) + a(n-3) + 2*a(n-4) - a(n-5) for n>6.

Empirical g.f.: x*(48 - 106*x + 21*x^2 + 78*x^3 - 47*x^4 + 3*x^5) / ((1 - x)^3*(1 - x - x^2)). - Colin Barker, Aug 30 2018

EXAMPLE

Some solutions for n=3:

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

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

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

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

CROSSREFS

Cf. A224550.

Sequence in context: A058229 A260106 A260099 * A247720 A204647 A260980

Adjacent sequences:  A224543 A224544 A224545 * A224547 A224548 A224549

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 10 2013

STATUS

approved

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Last modified October 15 21:38 EDT 2021. Contains 348034 sequences. (Running on oeis4.)