cp's OEIS Frontend

A189436 Number of 4 X n array permutations with each element not moving, or moving one space N, SW or SE.

%I A189436 #8 May 02 2018 08:06:08
%S A189436 1,9,31,140,571,2413,10069,42205,176624,739573,3096173,12962845,
%T A189436 54270579,227212636,951259751,3982596009,16673747193,69807202249,
%U A189436 292258553696,1223585260409,5122727328297,21447083573633,89791504401207
%N A189436 Number of 4 X n array permutations with each element not moving, or moving one space N, SW or SE.
%C A189436 Row 4 of A189435.
%H A189436 R. H. Hardin, <a href="/A189436/b189436.txt">Table of n, a(n) for n = 1..200</a>
%F A189436 Empirical: a(n) = 4*a(n-1) +2*a(n-2) -6*a(n-3) +4*a(n-4) -a(n-5).
%F A189436 Empirical g.f.: x*(1 + 5*x - 7*x^2 + 4*x^3 - x^4) / (1 - 4*x - 2*x^2 + 6*x^3 - 4*x^4 + x^5). - _Colin Barker_, May 02 2018
%e A189436 Some solutions for 4 X 3:
%e A189436 ..0..1..5....0..1..2....0..4..5....3..4..2....0..4..5....0..4..5....0..4..5
%e A189436 ..6..2..8....3..4..5....3..2..1....1..0..5....3..2..1....6..2..1....1..2..8
%e A189436 ..4..3.11....9.10..8....9.10..8....6..7..8....6.10.11....9..3..8....6..3.11
%e A189436 ..9.10..7....7..6.11....7..6.11....9.10.11....9..8..7....7.10.11....9.10..7
%Y A189436 Cf. A189435.
%K A189436 nonn
%O A189436 1,2
%A A189436 _R. H. Hardin_, Apr 22 2011