cp's OEIS Frontend

A259421 Number of (n+1) X (2+1) 0..1 arrays with each 2 X 2 subblock having clockwise pattern 0000 0001 0011 or 0111.

%I A259421 #8 Dec 25 2018 08:30:22
%S A259421 43,243,1366,7695,43347,244228,1376077,7753553,43687910,246163281,
%T A259421 1387029593,7815349472,44036333771,248126951851,1398095180302,
%U A259421 7877701886559,44387669863035,250106600625676,1409249728938893
%N A259421 Number of (n+1) X (2+1) 0..1 arrays with each 2 X 2 subblock having clockwise pattern 0000 0001 0011 or 0111.
%H A259421 R. H. Hardin, <a href="/A259421/b259421.txt">Table of n, a(n) for n = 1..210</a>
%F A259421 Empirical: a(n) = 6*a(n-1) + 2*a(n-2) - 22*a(n-3) - 6*a(n-4) + 6*a(n-5) + a(n-6).
%F A259421 Empirical g.f.: x*(43 - 15*x - 178*x^2 - 41*x^3 + 49*x^4 + 8*x^5) / (1 - 6*x - 2*x^2 + 22*x^3 + 6*x^4 - 6*x^5 - x^6). - _Colin Barker_, Dec 25 2018
%e A259421 Some solutions for n=4:
%e A259421 ..1..1..0....1..0..0....1..0..0....0..0..1....1..1..1....1..1..0....1..0..1
%e A259421 ..0..1..0....0..0..0....0..0..0....0..0..1....0..1..0....0..1..1....1..0..1
%e A259421 ..1..1..0....1..1..0....1..1..1....1..0..0....0..0..0....0..0..1....0..0..1
%e A259421 ..0..1..0....0..1..0....0..0..1....1..1..0....0..0..0....1..1..1....0..0..0
%e A259421 ..0..1..0....0..1..0....1..1..1....0..1..1....0..1..1....0..0..1....0..1..1
%Y A259421 Column 2 of A259427.
%K A259421 nonn
%O A259421 1,1
%A A259421 _R. H. Hardin_, Jun 26 2015