A228733 Number of arrays of the median of three adjacent elements of some length n+2 0..1 array.

2, 4, 8, 16, 28, 50, 88, 156, 278, 496, 886, 1582, 2824, 5040, 8994, 16050, 28642, 51114, 91218, 162788, 290512, 518448, 925222, 1651150, 2946640, 5258570, 9384438, 16747458, 29887496, 53337194, 95185500, 169867942, 303146148, 540994292

Offset

1,1

Comments

Column 1 of A228740

Links

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

Formula

Empirical: a(n) = 2*a(n-1) -a(n-3) +a(n-5).

Empirical: G.f. -2*x*(1+x)*(x^2-x+1) / ( -1+2*x-x^3+x^5 ). - R. J. Mathar, Sep 02 2013

Example

All solutions for n=4
..1..1..0..0..1..1..1..0..0..1..0..0..1..1..0..0
..0..1..0..0..0..1..0..1..1..1..0..1..1..0..1..0
..1..1..1..1..0..1..0..1..0..0..0..0..0..1..1..0
..1..1..1..0..1..0..0..0..0..0..1..1..1..0..1..0

Crossrefs

Sequence in context: A227036 A172020 A209410 * A318767 A208531 A349052

Adjacent sequences: A228730 A228731 A228732 * A228734 A228735 A228736

Keyword

nonn

Author

R. H. Hardin, Sep 01 2013

Status

approved