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A224548 Number of (n+1) X 7 0..1 matrices with each 2 X 2 subblock idempotent. 1
132, 218, 302, 448, 635, 916, 1323, 1941, 2887, 4363, 6688, 10383, 16288, 25764, 41012, 65594, 105273, 169374, 272985, 440519, 711477, 1149773, 1858822, 3005953, 4861910, 7864766, 12723338, 20584516, 33304007, 53884408, 87184023, 141063753 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 6 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*(132 - 310*x + 90*x^2 + 198*x^3 - 129*x^4 + 10*x^5) / ((1 - x)^3*(1 - x - x^2)). - Colin Barker, Aug 31 2018

EXAMPLE

Some solutions for n=3:

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

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

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

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

CROSSREFS

Cf. A224550.

Sequence in context: A102474 A015235 A204649 * A253510 A253503 A195674

Adjacent sequences:  A224545 A224546 A224547 * A224549 A224550 A224551

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 10 2013

STATUS

approved

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Last modified April 19 20:04 EDT 2019. Contains 322291 sequences. (Running on oeis4.)