A228736 Number of arrays of the median of three adjacent elements of some length-(n+2) 0..4 array.

5, 25, 125, 545, 1943, 6797, 23627, 83391, 298239, 1073743, 3873051, 13959617, 50261845, 180829983, 650385801, 2339156205, 8413500735, 30263904639, 108865370619, 391615337877, 1408733302733, 5067520822187, 18228904185829

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..114

Formula

Empirical: a(n) = 5*a(n-1) -4*a(n-2) -10*a(n-3) +16*a(n-4) +34*a(n-5) -46*a(n-6) +18*a(n-7) +15*a(n-8) +8*a(n-9) +129*a(n-10) +8*a(n-11) -283*a(n-12) -285*a(n-13) +291*a(n-14) +129*a(n-15) -281*a(n-16) -492*a(n-17) +132*a(n-18) +913*a(n-19) +760*a(n-20) +57*a(n-21) -727*a(n-22) -370*a(n-23) +74*a(n-24) +38*a(n-25) -59*a(n-26) -628*a(n-27) -241*a(n-28) +448*a(n-29) +443*a(n-30) +391*a(n-31) -32*a(n-32) -342*a(n-33) -158*a(n-34) -36*a(n-35) +40*a(n-36) +75*a(n-37) +13*a(n-38) -8*a(n-39) -4*a(n-40) -5*a(n-41) +a(n-43)

Example

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

Crossrefs

Column 4 of A228740.

Sequence in context: A337950 A366323 A267780 * A126642 A269615 A269579

Adjacent sequences: A228733 A228734 A228735 * A228737 A228738 A228739

Keyword

nonn

Author

R. H. Hardin Sep 01 2013

Status

approved