cp's OEIS Frontend

A267729 Number of n X 2 0..1 arrays with every repeated value in every row and column greater than or equal to the previous repeated value.

%I A267729 #7 Mar 21 2018 09:40:11
%S A267729 4,16,64,225,784,2601,8464,26896,84100,259081,788544,2374681,7086244,
%T A267729 20976400,61653904,180069561,522945424,1510954641,4345446400,
%U A267729 12444741136,35502850084,100926300721,285976813824,807886380625,2275928269924
%N A267729 Number of n X 2 0..1 arrays with every repeated value in every row and column greater than or equal to the previous repeated value.
%C A267729 Column 2 of A267735.
%H A267729 R. H. Hardin, <a href="/A267729/b267729.txt">Table of n, a(n) for n = 1..210</a>
%F A267729 Empirical: a(n) = 6*a(n-1) - 6*a(n-2) - 19*a(n-3) + 24*a(n-4) + 24*a(n-5) - 19*a(n-6) - 6*a(n-7) + 6*a(n-8) - a(n-9).
%F A267729 Empirical g.f.: x*(4 - 8*x - 8*x^2 + 13*x^3 + 26*x^4 - 17*x^5 - 7*x^6 + 6*x^7 - x^8) / ((1 + x)^3*(1 - 3*x + x^2)^3). - _Colin Barker_, Mar 21 2018
%e A267729 Some solutions for n=4:
%e A267729 ..0..0....0..1....0..1....1..0....1..1....0..0....1..1....0..0....1..1....0..1
%e A267729 ..1..0....0..0....0..1....0..0....1..1....1..0....0..0....0..0....1..1....1..0
%e A267729 ..0..0....1..0....0..1....1..1....0..1....0..1....1..1....0..0....0..0....1..1
%e A267729 ..0..1....1..0....1..1....0..0....1..0....0..1....1..0....1..0....1..1....1..0
%Y A267729 Cf. A267735.
%K A267729 nonn
%O A267729 1,1
%A A267729 _R. H. Hardin_, Jan 20 2016