A224726 Number of (n+3) X 9 0..2 matrices with each 4 X 4 subblock idempotent.

5737, 4129, 4868, 5371, 5727, 7090, 9090, 11457, 14037, 17836, 23484, 31351, 41643, 55578, 74998, 102125, 139377, 190396, 260660, 357879, 492171, 677302, 932510, 1284753, 1771097, 2442380, 3368672, 4647011, 6411491, 8847050, 12208690

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..122

Formula

Empirical: a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) + 2*a(n-4) - 5*a(n-5) + 4*a(n-6) - a(n-7) - a(n-8) + 2*a(n-9) - a(n-10) for n>12.

Empirical g.f.: x*(5737 - 13082*x + 9692*x^2 - 2583*x^3 - 11385*x^4 + 21581*x^5 - 12409*x^6 + 2549*x^7 + 5641*x^8 - 8500*x^9 + 2710*x^10 + 37*x^11) / ((1 - x)^3*(1 + x)*(1 + x^2)*(1 - x - x^4)). - Colin Barker, Sep 04 2018

Example

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

Crossrefs

Column 6 of A224728.

Sequence in context: A252422 A183647 A028547 * A378491 A043484 A163027

Adjacent sequences: A224723 A224724 A224725 * A224727 A224728 A224729

Keyword

nonn

Author

R. H. Hardin, Apr 16 2013

Status

approved