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A224602 Number of (n+2) X 6 0..2 matrices with each 3 X 3 subblock idempotent. 1
416, 449, 571, 666, 906, 1247, 1657, 2280, 3216, 4533, 6443, 9258, 13358, 19335, 28093, 40916, 59680, 87165, 127435, 186430, 272870, 399539, 585161, 857180, 1255824, 1840045, 2696239, 3951030, 5789994, 8485103, 12434953, 18223716 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 4 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*(416 - 1215*x + 1271*x^2 - 1004*x^3 + 1087*x^4 - 688*x^5 + 128*x^6 + 4*x^7) / ((1 - x)^3*(1 - x - x^3)). - Colin Barker, Sep 01 2018
EXAMPLE
Some solutions for n=3:
..1..0..0..0..0..0....0..0..0..0..0..0....0..1..0..0..0..1....1..0..0..0..0..0
..1..0..0..0..1..0....0..0..0..0..0..0....0..1..0..0..0..2....0..0..0..0..0..0
..0..0..0..0..1..0....0..0..0..0..0..1....0..1..0..0..0..1....0..0..0..0..0..1
..0..0..0..0..1..0....0..0..0..0..0..1....0..1..0..0..0..1....0..0..0..0..0..1
..0..0..0..0..1..0....0..0..0..0..0..1....0..2..0..0..0..1....0..0..0..0..0..1
CROSSREFS
Cf. A224606.
Sequence in context: A306381 A172779 A056068 * A249006 A249471 A246897
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 11 2013
STATUS
approved

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Last modified June 15 02:47 EDT 2024. Contains 373402 sequences. (Running on oeis4.)