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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
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 * A345536 A345788 A261708
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 11 2013
STATUS
approved

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Last modified June 24 01:53 EDT 2024. Contains 373661 sequences. (Running on oeis4.)