A228743 Number of arrays of the median of three adjacent elements of some length 8 0..n array.

50, 447, 2072, 6797, 17986, 41083, 84288, 159321, 282274, 474551, 763896, 1185509, 1783250, 2610931, 3733696, 5229489, 7190610, 9725359, 12959768, 17039421, 22131362, 28426091, 36139648, 45515785, 56828226, 70383015, 86520952

Offset

1,1

Comments

Row 6 of A228740

Links

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

Formula

Empirical: a(n) = (n+1)*(11*n^5+199*n^4+706*n^3+824*n^2+420*n+90)/90.

Empirical: G.f. -x*(50+97*x-7*x^2-70*x^3+24*x^4-7*x^5+x^6) / (x-1)^7 . - R. J. Mathar, Sep 02 2013

Example

Some solutions for n=4
..2..3..1..2..4..3..4..4..0..4..2..1..0..3..4..2
..1..4..3..2..2..2..0..3..3..2..4..2..2..3..0..0
..2..1..0..4..2..1..0..4..3..2..0..3..1..3..0..3
..1..1..4..4..1..0..2..2..3..2..4..3..3..3..3..0
..4..1..0..4..4..1..2..3..1..3..0..0..1..0..3..2
..3..4..0..2..2..3..4..2..0..2..0..0..0..1..4..0

Crossrefs

Sequence in context: A293608 A111341 A222693 * A019561 A164757 A189415

Adjacent sequences: A228740 A228741 A228742 * A228744 A228745 A228746

Keyword

nonn

Author

R. H. Hardin, Sep 01 2013

Status

approved