A264014 Number of (n+1) X (4+1) arrays of permutations of 0..n*5+4 with each element having index change +-(.,.) 0,0 1,2 or 2,2.

8, 105, 1573, 20570, 269225, 3524125, 46131250, 603865625, 7904703125, 103473906250, 1354491015625, 17730517578125, 232095488281250, 3038169384765625, 39770153564453125, 520598068847656250

Offset: 1

Author

R. H. Hardin, Nov 01 2015

Keywords

• nonn

Examples

			Some solutions for n=4:
.12.13..9..3..4....7..1..9..3..4....7.13.14..3..4....7.13..9..3..4
..5..6.19..8..2....5.18..0..8..2...17.18.19..8..9...12.18..0..8..2
.10.18..0..1.14...10.11.24.13.14...10.11..0..1..2...17.23..5..1.14
.22.16.24.11..7...22.23.17..6.19...15.23..5..6.12...22.16.10..6.19
.20.21.15.23.17...20.21.15.16.12...20.21.22.16.24...20.21.15.11.24
		

Links

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

Crossrefs

Column 4 of A264017.

Formula

Empirical: a(n) = 15*a(n-1) - 25*a(n-2) for n>4.

Empirical g.f.: x*(1 - 2*x)*(8 + x + 200*x^2) / (1 - 15*x + 25*x^2). - Colin Barker, Jan 03 2019