A264266 Number of (n+1) X (2+1) arrays of permutations of 0..n*3+2 with each element having index change +-(.,.) 0,0 1,0 or 1,2.

10, 48, 305, 1800, 10933, 65856, 397970, 2402455, 14508869, 87609600, 529045373, 3194668217, 19291314050, 116492151552, 703447966957, 4247829912600, 25650883291001, 154895038005840, 935346867163930, 5648171599648271

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-1) + 16*a(n-2) - 16*a(n-3) - 41*a(n-4) + 16*a(n-5) + 16*a(n-6) - 4*a(n-7) - a(n-8).

Empirical g.f.: x*(10 + 8*x - 47*x^2 - 28*x^3 + 31*x^4 + 12*x^5 - 5*x^6 - x^7) / ((1 + x - x^2)*(1 - x - x^2)*(1 - 4*x - 13*x^2 + 4*x^3 + x^4)). - Colin Barker, Jan 07 2019

Example

Some solutions for n=4:
..3..4..2....5..1..2....0..4..5....3..1..2....0..1..2....3..4..5....3..1..2
..0..1..5....0..7..8....3..1..2....0..4..5....3..7..8....0..1..2....8..7..0
..9..7..8....6..4..3....9..7.11....6..7.11....6..4..5....6.10..8...11..4..5
.14.13..6...14.13.11....6.13..8...12.13..8....9.10.14...12..7.11...12.10..6
.12.10.11...12.10..9...12.10.14....9.10.14...12.13.11....9.13.14....9.13.14

Crossrefs

Column 2 of A264272.

Sequence in context: A349948 A330170 A126734 * A048698 A045770 A217165

Adjacent sequences: A264263 A264264 A264265 * A264267 A264268 A264269

Keyword

nonn

Author

R. H. Hardin, Nov 10 2015

Status

approved