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A224686 Number of (n+4) X 8 0..1 matrices with each 5 X 5 subblock idempotent. 1
3465, 1720, 1896, 2166, 2429, 2646, 3214, 4122, 5307, 6699, 8253, 10313, 13224, 17256, 22621, 29474, 38326, 50021, 65685, 86644, 114391, 150918, 199073, 262818, 347453, 459759, 608521, 805360, 1065871, 1410937, 1868234, 2474211, 3276950 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 3*a(n-1) - 2*a(n-2) - 2*a(n-3) + 3*a(n-4) - 2*a(n-6) + 2*a(n-8) - a(n-9) for n>13.

Empirical g.f.: x*(3465 - 8675*x + 3666*x^2 + 6848*x^3 - 7232*x^4 - 1677*x^5 + 5708*x^6 + 1572*x^7 - 5764*x^8 + 1869*x^9 + 158*x^10 + 56*x^11 + 4*x^12) / ((1 - x)^3*(1 + x)*(1 - x + x^2)*(1 - x^2 - x^3)). - Colin Barker, Sep 03 2018

EXAMPLE

Some solutions for n=2:

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

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

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

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

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

CROSSREFS

Column 4 of A224690.

Sequence in context: A235586 A252967 A252959 * A125017 A307111 A307098

Adjacent sequences:  A224683 A224684 A224685 * A224687 A224688 A224689

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 15 2013

STATUS

approved

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Last modified January 28 14:26 EST 2022. Contains 350656 sequences. (Running on oeis4.)