cp's OEIS Frontend

A189644 Number of n X 3 array permutations with each element moving zero or one space horizontally, diagonally or antidiagonally.

%I A189644 #9 May 02 2018 14:19:48
%S A189644 3,33,263,2161,17655,144353,1180167,9648721,78885143,644942273,
%T A189644 5272862503,43109407281,352450114615,2881530764193,23558566731847,
%U A189644 192608065601041,1574708145738583,12874360876413313,105257071556189543
%N A189644 Number of n X 3 array permutations with each element moving zero or one space horizontally, diagonally or antidiagonally.
%C A189644 Column 3 of A189650.
%H A189644 R. H. Hardin, <a href="/A189644/b189644.txt">Table of n, a(n) for n = 1..200</a>
%F A189644 Empirical: a(n) = 9*a(n-1) - 6*a(n-2) - 8*a(n-3) + 16*a(n-4).
%F A189644 Empirical g.f.: x*(3 + 6*x - 16*x^2 + 16*x^3) / (1 - 9*x + 6*x^2 + 8*x^3 - 16*x^4). - _Colin Barker_, May 02 2018
%e A189644 Some solutions for 4 X 3:
%e A189644 ..0..1..2....1..0..2....1..0..4....4..0..2....0..2..1....0..3..4....1..0..2
%e A189644 ..7..5..4....3..8..5....3..2..5....3..5..1....3..4..5....1..2..7....3..6..5
%e A189644 ..6..3.10....6..9..4...10..6..7...10..6..8....7..9..8....6..5.10....7..8..4
%e A189644 ..9..8.11....7.11.10....9..8.11....9.11..7...10..6.11....9..8.11....9.10.11
%Y A189644 Cf. A189650.
%K A189644 nonn
%O A189644 1,1
%A A189644 _R. H. Hardin_, Apr 24 2011