A264167 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 -2,-1 or -1,-2.

4, 25, 98, 418, 1862, 8007, 34539, 149808, 648436, 2805250, 12142877, 52558637, 227471330, 984523558, 4261166714, 18442796291, 79822557139, 345481774068, 1495286247768, 6471776351478, 28010620722521, 121233307002413

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + 7*a(n-2) + 23*a(n-3) + 35*a(n-4) + 18*a(n-5) for n>7.

Empirical g.f.: x*(4 + 21*x + 45*x^2 + 53*x^3 + 43*x^4 + 18*x^5 + 4*x^6) / (1 - x - 7*x^2 - 23*x^3 - 35*x^4 - 18*x^5). - Colin Barker, Jan 05 2019

Example

Some solutions for n=4:
..5..1..2....5..8..1....5..0..1....7..0..1....0..8..1....7..0..1....5..0..1
..0..3..4....0..3..2....3..4..2....3.11..2...10..3..2....3..4..2....8..4..2
.11..6..8....6..4..7....6..7..8....6..4..5...13..4..5...13..6..5....3.14..7
.14..7.10...14.10.11...14..9.10...14..9..8....6..7.11...14..9..8....6..9.10
..9.12.13....9.12.13...12.13.11...12.10.13....9.12.14...12.10.11...12.13.11

Crossrefs

Column 2 of A264172.

Sequence in context: A195509 A027949 A226547 * A152215 A231175 A082044

Adjacent sequences: A264164 A264165 A264166 * A264168 A264169 A264170

Keyword

nonn

Author

R. H. Hardin, Nov 06 2015

Status

approved