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A224603 Number of (n+2) X 7 0..2 matrices with each 3 X 3 subblock idempotent. 1
628, 630, 782, 906, 1202, 1609, 2091, 2817, 3895, 5397, 7564, 10745, 15361, 22074, 31895, 46256, 67251, 97985, 142995, 208912, 305472, 446948, 654244, 958000, 1403129, 2055448, 3011414, 4412397, 6465584, 9474619, 13884516, 20347476 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 5 of A224606.

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*(628 - 1882*x + 2030*x^2 - 1582*x^3 + 1632*x^4 - 1037*x^5 + 203*x^6 + 5*x^7) / ((1 - x)^3*(1 - x - x^3)). - Colin Barker, Sep 01 2018

EXAMPLE

Some solutions for n=3:

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

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

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

..0..0..0..0..0..0..1....2..0..0..0..0..0..0....0..1..0..0..0..0..1

..0..0..0..0..0..0..1....0..0..0..0..1..1..1....0..2..0..0..0..0..1

CROSSREFS

Cf. A224606.

Sequence in context: A158382 A188362 A098260 * A261708 A098261 A256937

Adjacent sequences:  A224600 A224601 A224602 * A224604 A224605 A224606

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 11 2013

STATUS

approved

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Last modified March 28 05:38 EDT 2020. Contains 333073 sequences. (Running on oeis4.)