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A224547
Number of (n+1) X 6 0..1 matrices with each 2 X 2 subblock idempotent.
1
80, 137, 193, 294, 428, 635, 943, 1420, 2162, 3333, 5193, 8166, 12936, 20611, 32983, 52952, 85210, 137349, 221653, 357998, 578544, 935327, 1512543, 2446424, 3957398, 6402125, 10357693, 16757850, 27113432, 43869023, 70980043, 114846496
OFFSET
1,1
COMMENTS
Column 5 of A224550.
LINKS
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*(80 - 183*x + 45*x^2 + 127*x^3 - 80*x^4 + 6*x^5) / ((1 - x)^3*(1 - x - x^2)). - Colin Barker, Aug 30 2018
EXAMPLE
Some solutions for n=3:
..1..1..1..1..0..1....1..0..0..1..0..1....1..0..0..0..0..0....1..1..0..0..0..1
..0..0..0..0..0..1....1..0..0..1..0..1....0..0..0..0..0..0....0..0..0..0..0..1
..0..0..0..0..0..1....0..0..0..1..0..1....0..0..0..0..0..0....0..0..0..0..0..1
..0..0..0..0..0..1....0..0..0..1..0..1....0..0..0..0..1..1....0..0..0..0..0..1
CROSSREFS
Cf. A224550.
Sequence in context: A365867 A349307 A349308 * A204648 A202447 A202440
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 10 2013
STATUS
approved