A264211 Number of (n+1) X (2+1) arrays of permutations of 0..n*3+2 with each element having directed index change 0,0 0,1 1,0 -1,0 or 0,-2.

17, 96, 596, 3610, 21997, 133836, 814609, 4957760, 30173957, 183643896, 1117690025, 6802461466, 41401001380, 251973919068, 1533558468205, 9333511899338, 56805427515893, 345728020681728, 2104162744903661

Offset

1,1

Links

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

Formula

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

Empirical g.f.: x*(17 - 6*x - 31*x^2 + 18*x^3 + 34*x^4 - 13*x^6 - 2*x^7) / (1 - 6*x - 3*x^2 + 16*x^3 - 3*x^4 - 16*x^5 - 3*x^6 + 6*x^7 + x^8). - Colin Barker, Jan 06 2019

Example

Some solutions for n=4:
..0..1..2....0..4..1....2..0..1....0..4..2....2..0..1....3..4..2....0..1..2
..5..7..4....5..3..2....6..7..8....3..1..5....5..3..4....0..1..5....6..4..5
..3..6..8....9..6..7....3..4..5....8..7.11....8..6..7....9..7..8....3..7.11
.12.13.11...12.10..8....9.10.11....6.13.10...12..9.10....6.13.10...12.10..8
..9.10.14...14.13.11...12.13.14....9.12.14...14.13.11...14.12.11....9.13.14

Crossrefs

Column 2 of A264217.

Sequence in context: A119783 A199042 A362305 * A094407 A131204 A070186

Adjacent sequences: A264208 A264209 A264210 * A264212 A264213 A264214

Keyword

nonn

Author

R. H. Hardin, Nov 08 2015

Status

approved