A224622 Number of (n+4) X 9 0..2 matrices with each 5 X 5 subblock idempotent.

39001, 23453, 28058, 30723, 32204, 33115, 41120, 53862, 69089, 85561, 102702, 127605, 165006, 217389, 285998, 371501, 481659, 628969, 828412, 1096213, 1449265, 1912222, 2522235, 3331436, 4408182, 5837723, 7729963, 10231957, 13542892

Offset

1,1

Comments

Column 5 of A224625.

Links

R. H. Hardin, Table of n, a(n) for n = 1..53

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*(39001 - 132551*x + 168252*x^2 - 96795*x^3 + 22849*x^4 - 39143*x^5 + 100600*x^6 - 84723*x^7 + 22198*x^8 + 256*x^9 + 50*x^10 + 5*x^11) / ((1 - x)^3*(1 - x + x^2)*(1 - x^2 - x^3)). - Colin Barker, Sep 02 2018

Example

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

Crossrefs

Cf. A224625.

Sequence in context: A206597 A088237 A031644 * A233955 A250515 A031667

Adjacent sequences: A224619 A224620 A224621 * A224623 A224624 A224625

Keyword

nonn

Author

R. H. Hardin, Apr 12 2013

Status

approved