cp's OEIS Frontend

A209101 Number of 2 X n 0..2 arrays with new values 0..2 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.

%I A209101 #9 Jul 08 2018 10:48:15
%S A209101 2,11,76,520,3552,24256,165632,1131008,7723008,52736000,360103936,
%T A209101 2458943488,16790716416,114654183424,782907736064,5346028421120,
%U A209101 36504965480448,249271496474624,1702132247953408,11622886011830272
%N A209101 Number of 2 X n 0..2 arrays with new values 0..2 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.
%C A209101 Row 2 of A209100.
%H A209101 R. H. Hardin, <a href="/A209101/b209101.txt">Table of n, a(n) for n = 1..210</a>
%F A209101 Empirical: a(n) = 8*a(n-1) - 8*a(n-2) for n>3.
%F A209101 Empirical g.f.: x*(2 - 5*x + 4*x^2) / (1 - 8*x + 8*x^2). - _Colin Barker_, Jul 08 2018
%e A209101 Some solutions for n=4:
%e A209101 ..0..0..1..2....0..0..1..1....0..0..0..1....0..0..1..1....0..0..0..0
%e A209101 ..1..2..0..0....2..0..0..1....2..1..0..2....1..0..2..0....1..1..2..0
%Y A209101 Cf. A209100.
%K A209101 nonn
%O A209101 1,1
%A A209101 _R. H. Hardin_, Mar 05 2012