A224566 Number of (n+3) X 9 0..1 matrices with each 4 X 4 subblock idempotent.

1345, 775, 929, 1091, 1233, 1550, 1997, 2558, 3206, 4115, 5408, 7202, 9577, 12793, 17227, 23383, 31835, 43423, 59358, 81365, 111733, 153597, 211297, 290908, 400784, 552420, 761645, 1050373, 1448862, 1998871, 2757982, 3805701, 5251782, 7247744

Offset

1,1

Comments

Column 6 of A224568.

Links

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

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*(1345 - 3260*x + 2639*x^2 - 716*x^3 - 2718*x^4 + 5370*x^5 - 3408*x^6 + 692*x^7 + 1366*x^8 - 2111*x^9 + 762*x^10 + 27*x^11) / ((1 - x)^3*(1 + x)*(1 + x^2)*(1 - x - x^4)). - Colin Barker, Sep 01 2018

Example

Some solutions for n=3:
..1..0..0..0..0..0..1..0..0....0..1..0..0..0..0..0..0..0
..1..0..0..0..0..0..1..0..0....0..1..0..0..0..0..0..1..0
..1..0..0..0..0..0..1..0..0....0..1..0..0..0..0..0..1..0
..0..0..0..0..0..0..1..0..0....0..1..0..0..0..0..0..1..0
..1..0..0..0..0..0..1..0..0....0..0..0..0..0..0..0..1..0
..0..0..0..0..0..0..1..0..0....0..1..0..0..0..0..0..1..0

Crossrefs

Cf. A224568.

Sequence in context: A239192 A172686 A270110 * A053770 A094037 A250088

Adjacent sequences: A224563 A224564 A224565 * A224567 A224568 A224569

Keyword

nonn

Author

R. H. Hardin, Apr 10 2013

Status

approved