|
%I #10 Jan 06 2019 07:56:48
%S 4,17,56,172,561,1826,5880,18993,61424,198472,641297,2072482,6697372,
%T 21642593,69939048,226011412,730364961,2360204994,7627103920,
%U 24647309729,79648825312,257388562256,831762066401,2687874415810,8685980265204
%N Number of (1+1) X (n+1) arrays of permutations of 0..n*2+1 with each element having directed index change 0,0 0,1 1,0 -1,0 or 0,-2.
%H R. H. Hardin, <a href="/A264218/b264218.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 2*a(n-1) + 2*a(n-2) + 6*a(n-3) + 2*a(n-4) - 2*a(n-5) - a(n-6).
%F Empirical g.f.: x*(4 + 9*x + 14*x^2 + 2*x^3 - 5*x^4 - 2*x^5) / (1 - 2*x - 2*x^2 - 6*x^3 - 2*x^4 + 2*x^5 + x^6). - _Colin Barker_, Jan 06 2019
%e Some solutions for n=4:
%e ..0..1..4..2..9....5..6..1..2..9....0..3..1..2..4....5..1..4..2..3
%e ..5..6..7..3..8....0..8..7..3..4....5..8..6..7..9....0..6..7..8..9
%Y Row 1 of A264217.
%K nonn
%O 1,1
%A _R. H. Hardin_, Nov 08 2015
|
