A264360 Number of (n+1) X (4+1) arrays of permutations of 0..n*5+4 with each element having directed index change 0,0 0,2 1,0 or -1,-2.

18, 120, 936, 7168, 54720, 418992, 3204336, 24514000, 187528608, 1434558960, 10974201216, 83950973056, 642212998704, 4912836726000, 37582492431888, 287500651922848, 2199338537486832, 16824622797993408, 128705939150098368

Offset: 1

Author

R. H. Hardin, Nov 12 2015

Keywords

• nonn

Examples

			Some solutions for n=4:
..0..1..2..3..4....0..1..2..3..4....7..8..2..1..4....0..1..2..3..4
..5..6..7..8..9....5.13.14..8..7....0..6..5..3..9...12..6..7..8..9
.10.11.12.13.14...10..6.19.11..9...10.11.12.13.14....5.18.10.11.14
.15.16.24.18.19...15.23.12.18.17...22.16.17.18.19...22.16.17.13.19
.20.21.17.23.22...20.16.22.21.24...15.21.20.23.24...15.21.20.23.24
		

Links

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

Crossrefs

Column 4 of A264364.

Formula

Empirical: a(n) = 3*a(n-1) + 28*a(n-2) + 57*a(n-3) + 10*a(n-4) - 24*a(n-5) + 8*a(n-6).

Empirical g.f.: 2*x*(9 + 33*x + 36*x^2 - 13*x^3 - 6*x^4 + 4*x^5) / (1 - 3*x - 28*x^2 - 57*x^3 - 10*x^4 + 24*x^5 - 8*x^6). - Colin Barker, Jan 07 2019