A228741 Number of arrays of the median of three adjacent elements of some length-6 0..n array.

16, 77, 232, 545, 1096, 1981, 3312, 5217, 7840, 11341, 15896, 21697, 28952, 37885, 48736, 61761, 77232, 95437, 116680, 141281, 169576, 201917, 238672, 280225, 326976, 379341, 437752, 502657, 574520, 653821, 741056, 836737, 941392, 1055565

Offset

1,1

Links

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

Formula

Empirical: a(n) = (n+1)*(2*n^3+10*n^2+9*n+3)/3.

Empirical: G.f. -x*(16-3*x+7*x^2-5*x^3+x^4) / (x-1)^5 . - R. J. Mathar, Sep 02 2013

Example

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

Crossrefs

Row 4 of A228740.

Sequence in context: A253691 A300919 A007834 * A346636 A200873 A082966

Adjacent sequences: A228738 A228739 A228740 * A228742 A228743 A228744

Keyword

nonn

Author

R. H. Hardin, Sep 01 2013

Status

approved