A264129 Number of (n+1) X (4+1) arrays of permutations of 0..n*5+4 with each element having index change +-(.,.) 0,0 0,2 or 1,2.

80, 1040, 13600, 178000, 2330000, 30500000, 399250000, 5226250000, 68412500000, 895531250000, 11722656250000, 153451562500000, 2008707031250000, 26294316406250000, 344197070312500000, 4505598144531250000

Offset: 1

Author

R. H. Hardin, Nov 03 2015

Keywords

• nonn

Examples

			Some solutions for n=4:
..0..8..4..3..2....0..3..9..1..4....0..1..4..3..2....0..8..2..3..4
..5.13..7..1..9....5..6.14..8..2....5..6..9..8..7...12.13.14..1..9
.10.11.14..6.12...17.13.12.11..7...12.11.10.13.14...10.18..5..6..7
.15.16.19.18.17...15.23.10.18.19...22.18.17.16.19...22.16.24.11.19
.20.21.24.23.22...20.21.22.16.24...20.23.15.21.24...20.21.15.23.17
		

Links

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

Crossrefs

Column 4 of A264131.

Formula

Empirical: a(n) = 15*a(n-1) - 25*a(n-2).

Empirical g.f.: 80*x*(1 - 2*x) / (1 - 15*x + 25*x^2). - Colin Barker, Jan 04 2019