cp's OEIS Frontend

A221899 Number of 2 X n arrays of occupancy after each element stays put or moves to some horizontal, vertical or antidiagonal neighbor, without move-in move-out straight through or left turns.

%I A221899 #8 Aug 11 2018 13:05:37
%S A221899 3,31,258,2241,19408,167960,1453952,12585637,108943526,943035150,
%T A221899 8163084148,70661144632,611655753520,5294603734144,45831055372945,
%U A221899 396721972412987,3434097733826959,29726176177614458,257315201439500033
%N A221899 Number of 2 X n arrays of occupancy after each element stays put or moves to some horizontal, vertical or antidiagonal neighbor, without move-in move-out straight through or left turns.
%C A221899 Row 2 of A221898.
%H A221899 R. H. Hardin, <a href="/A221899/b221899.txt">Table of n, a(n) for n = 1..210</a>
%F A221899 Empirical: a(n) = 5*a(n-1) + 26*a(n-2) + 45*a(n-3) + 34*a(n-4) - 2*a(n-5) - 4*a(n-6) + a(n-7).
%F A221899 Empirical g.f.: x*(3 + 16*x + 25*x^2 + 10*x^3 - 2*x^4 - 4*x^5 + x^6) / (1 - 5*x - 26*x^2 - 45*x^3 - 34*x^4 + 2*x^5 + 4*x^6 - x^7). - _Colin Barker_, Aug 11 2018
%e A221899 Some solutions for n=3:
%e A221899 ..0..2..3....0..0..0....0..3..0....2..0..2....1..1..2....0..4..1....1..2..1
%e A221899 ..1..0..0....3..2..1....2..0..1....2..0..0....0..2..0....0..1..0....0..1..1
%Y A221899 Cf. A221898.
%K A221899 nonn
%O A221899 1,1
%A A221899 _R. H. Hardin_, Jan 30 2013