A224687 Number of (n+4) X 9 0..1 matrices with each 5 X 5 subblock idempotent.

4405, 1938, 2136, 2429, 2700, 2926, 3540, 4514, 5773, 7247, 8885, 11074, 14173, 18466, 24167, 31439, 40832, 53255, 69901, 92177, 121653, 160449, 211594, 279310, 369226, 488541, 646574, 855673, 1132408, 1498978, 1984781, 2628534, 3481302

Offset

1,1

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) + 4*a(n-3) - a(n-4) + a(n-5) - 3*a(n-6) + 3*a(n-7) - a(n-8) for n>12.

Empirical g.f.: x*(4405 - 15682*x + 20814*x^2 - 12107*x^3 + 2453*x^4 - 4311*x^5 + 11733*x^6 - 9998*x^7 + 2523*x^8 + 122*x^9 + 42*x^10 + 5*x^11) / ((1 - x)^3*(1 - x + x^2)*(1 - x^2 - x^3)). - Colin Barker, Sep 03 2018

Example

Some solutions for n=2:
..1..1..1..1..1..0..0..1..1....1..0..0..0..0..0..0..0..0
..0..0..0..0..0..0..0..0..0....1..0..0..0..0..0..0..0..0
..0..0..0..0..0..0..0..0..0....0..0..1..0..1..0..1..0..0
..0..0..0..0..0..0..0..0..0....0..0..1..0..1..0..1..0..0
..0..0..0..0..0..0..0..0..0....0..0..0..0..0..0..0..0..0
..1..0..0..1..1..1..1..1..1....0..0..0..0..0..0..0..0..1

Crossrefs

Column 5 of A224690.

Sequence in context: A345184 A152931 A045013 * A050664 A303095 A039818

Adjacent sequences: A224684 A224685 A224686 * A224688 A224689 A224690

Keyword

nonn

Author

R. H. Hardin, Apr 15 2013

Status

approved