A264536 - OEIS

%I #7 Jan 08 2019 09:50:57

%S 1,4,13,29,89,261,673,1949,5545,15045,42609,119917,331641,931669,

%T 2611393,7272829,20371529,57014501,159195153,445435789,1245975065,

%U 3482261365,9739722849,27238546077,76152655081,212964930309,595543665073

%N Number of (3+1) X (n+1) arrays of permutations of 0..n*4+3 with each element having directed index change -2,-2 -1,0 0,1 or 1,0.

%H R. H. Hardin, <a href="/A264536/b264536.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) + 12*a(n-3) + 16*a(n-5).

%F Empirical g.f.: x*(1 + 3*x + 9*x^2 + 4*x^3 + 12*x^4) / ((1 + 2*x + 4*x^2)*(1 - 3*x + 2*x^2 - 4*x^3)). - _Colin Barker_, Jan 08 2019

%e Some solutions for n=4:

%e ..5.13.14..2..9....5.13.14..2..9....5..6.14..2..3...12.13..1..2..3

%e ..0..1..6..3..4....0..1.12..3..4....0..1.19..7..4....0.18.19..7..4

%e .15.16..7..8.19...15..6..7..8.19...15.16.17..8..9....5..6.11..8..9

%e .10.11.12.17.18...10.11.16.17.18...10.11.12.13.18...10.15.16.17.14

%Y Row 3 of A264534.

%K nonn

%O 1,2

%A _R. H. Hardin_, Nov 17 2015