A264337 Number of (n+1) X (4+1) arrays of permutations of 0..n*5+4 with each element having index change +-(.,.) 0,0 0,1 or 1,2.

181, 3567, 70669, 1399783, 27726581, 549201567, 10878455069, 215477871383, 4268134837381, 84542207852367, 1674592106593069, 33169925350906183, 657022055372706581, 13014137857695923967, 257780972182185860669

Offset

1,1

Links

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

Formula

Empirical: a(n) = 19*a(n-1) + 16*a(n-2).

Conjectures from Colin Barker, Jan 07 2019: (Start)

G.f.: x*(181 + 128*x) / (1 - 19*x - 16*x^2).

a(n) = (2^(-n)*((19-5*sqrt(17))^n*(-21+4*sqrt(17)) + (21+4*sqrt(17))*(19+5*sqrt(17))^n)) / sqrt(17).

(End)

Example

Some solutions for n=3:
..0..2..1..4..3....0..8..1..3..4....7..1..3..2..4....0..2..1..4..3
.12..6..7..9..8...12..5..7..9..2....5.13..0..8..9....5..6.14..9..8
.17.10..5.14.13...17.11.13..6.14...11.10.12..6.14...11.10.12.13..7
.16.15.18.11.19...15.16.10.18.19...15.17.16.19.18...16.15.18.17.19

Crossrefs

Column 4 of A264341.

Sequence in context: A069763 A264289 A200953 * A155018 A179814 A293655

Adjacent sequences: A264334 A264335 A264336 * A264338 A264339 A264340

Keyword

nonn

Author

R. H. Hardin, Nov 11 2015

Status

approved