cp's OEIS Frontend

A264544 Number of (n+1) X (2+1) arrays of permutations of 0..n*3+2 with each element having directed index change -1,1 -1,2 1,0 or 0,-1.

%I A264544 #8 Jan 08 2019 19:00:32
%S A264544 1,2,5,10,21,44,93,196,413,870,1833,3862,8137,17144,36121,76104,
%T A264544 160345,337834,711789,1499682,3159709,6657252,14026293,29552268,
%U A264544 62264245,131185742,276397777,582347822,1226959889,2585105520,5446608817
%N A264544 Number of (n+1) X (2+1) arrays of permutations of 0..n*3+2 with each element having directed index change -1,1 -1,2 1,0 or 0,-1.
%H A264544 R. H. Hardin, <a href="/A264544/b264544.txt">Table of n, a(n) for n = 1..210</a>
%F A264544 Empirical: a(n) = 2*a(n-1) + a(n-4).
%F A264544 Empirical g.f.: x*(1 + x^2) / (1 - 2*x - x^4). - _Colin Barker_, Jan 08 2019
%e A264544 Some solutions for n=4:
%e A264544 ..1..2..4....1..2..3....1..2..4....1..2..4....1..3..4....1..2..4....1..3..4
%e A264544 ..0..6..7....0..5..6....0..5..7....0..6..7....0..5..2....0..5..7....0..6..2
%e A264544 ..3..8..5....7..4..9....3..9.10....3..9..5....7..8.10....3..8.10....7..8..5
%e A264544 .10.12.13...10.12..8....6.12..8...10.12..8....6.12.13....6.12.13...10.12.13
%e A264544 ..9.14.11...13.14.11...13.14.11...13.14.11....9.14.11....9.14.11....9.14.11
%Y A264544 Column 2 of A264550.
%K A264544 nonn
%O A264544 1,2
%A A264544 _R. H. Hardin_, Nov 17 2015