cp's OEIS Frontend

A266543 Number of n X 4 binary arrays with rows and columns lexicographically nondecreasing and row and column sums nonincreasing.

%I A266543 #8 Jan 10 2019 08:08:25
%S A266543 2,4,6,12,16,27,36,57,76,114,149,213,276,379,485,645,811,1051,1304,
%T A266543 1652,2021,2511,3034,3709,4431,5338,6311,7510,8795,10352,12020,14010,
%U A266543 16142,18653,21340,24469,27813,31669,35786,40492,45507,51196,57252,64073,71324
%N A266543 Number of n X 4 binary arrays with rows and columns lexicographically nondecreasing and row and column sums nonincreasing.
%H A266543 R. H. Hardin, <a href="/A266543/b266543.txt">Table of n, a(n) for n = 1..179</a>
%F A266543 Empirical: a(n) = a(n-1) + 2*a(n-2) - a(n-3) - a(n-4) - a(n-5) - a(n-6) + 2*a(n-8) + 2*a(n-9) - a(n-11) - a(n-12) - a(n-13) - a(n-14) + 2*a(n-15) + a(n-16) - a(n-17).
%F A266543 Empirical g.f.: x*(2 + 2*x - 2*x^2 - 2*x^4 - x^5 + x^6 + 5*x^7 + 4*x^8 + 3*x^9 - x^10 - 2*x^11 - 2*x^12 - x^13 + 4*x^14 + 2*x^15 - 2*x^16) / ((1 - x)^6*(1 + x)^3*(1 + x^2)*(1 + x + x^2)*(1 + x + x^2 + x^3 + x^4)). - _Colin Barker_, Jan 10 2019
%e A266543 Some solutions for n=6:
%e A266543 ..0..0..1..1....0..0..1..1....0..1..1..1....0..1..1..1....0..0..1..1
%e A266543 ..0..1..0..1....0..1..0..0....1..0..1..1....1..0..0..1....0..1..0..1
%e A266543 ..0..1..1..0....1..0..0..0....1..1..0..0....1..0..1..0....0..1..1..0
%e A266543 ..1..0..0..0....1..0..0..0....1..1..0..0....1..1..0..0....1..0..0..1
%e A266543 ..1..0..0..0....1..0..0..0....1..1..0..0....1..1..0..0....1..0..1..0
%e A266543 ..1..0..0..0....1..0..0..0....1..1..0..0....1..1..0..0....1..1..0..0
%Y A266543 Column 4 of A266547.
%K A266543 nonn
%O A266543 1,1
%A A266543 _R. H. Hardin_, Dec 31 2015