A264492 Number of (4+1) X (n+1) arrays of permutations of 0..n*5+4 with each element having directed index change 2,-1 1,0 2,1 0,-1 -2,-2 or -1,0.

12, 16, 212, 788, 4772, 23076, 122628, 626276, 3250500, 16761124, 86652932, 447525860, 2312212676, 11944531620, 61707373956, 318782647652, 1646858513988, 8507781990436, 43951835558660, 227058335082212, 1172999888706500

Offset: 1

Author

R. H. Hardin, Nov 14 2015

Keywords

• nonn

Examples

			Some solutions for n=4:
..5..2..7..4..9....1..6.14..8..9....1..6..7..8..9....1..6..7..8..9
..0..1.12.13.14...10.11..2.13..4...10.11..2.13..4...10.18..2.13..4
.22.16.17..8..3....5..0.17.18..3....5..0.24.18..3...15..0.17.14..3
.20.21..6.23.24...20.21.22..7.24...20.21.22.23.14...20..5.22.23.24
.15.10.11.18.19...15.16.23.12.19...15.16.17.12.19...21.16.11.12.19
		

Links

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

Crossrefs

Row 4 of A264490.

Formula

Empirical: a(n) = a(n-1) + 16*a(n-2) + 24*a(n-3) + 16*a(n-4) + 32*a(n-5) + 32*a(n-6).

Empirical g.f.: 4*x*(3 + x + x^2 + 8*x^3 + 4*x^4 - 8*x^5) / ((1 + 2*x)*(1 - 3*x - 10*x^2 - 4*x^3 - 8*x^4 - 16*x^5)). - Colin Barker, Jan 08 2019