cp's OEIS Frontend

A203095 Number of n X 2 0..3 arrays with every nonzero element less than or equal to some horizontal or vertical neighbor.

%I A203095 #8 Jun 04 2018 03:11:45
%S A203095 4,84,1080,12260,143510,1705124,20174774,238288768,2816078514,
%T A203095 33286887866,393430889634,4650009454296,54959608405434,
%U A203095 649582808767618,7677588567818968,90743395882037312,1072519744806185004
%N A203095 Number of n X 2 0..3 arrays with every nonzero element less than or equal to some horizontal or vertical neighbor.
%C A203095 Column 2 of A203101.
%H A203095 R. H. Hardin, <a href="/A203095/b203095.txt">Table of n, a(n) for n = 1..210</a>
%F A203095 Empirical: a(n) = 10*a(n-1) -a(n-2) +236*a(n-3) +270*a(n-4) +945*a(n-5) +532*a(n-6) +576*a(n-7).
%F A203095 Empirical g.f.: 2*x*(2 + 22*x + 122*x^2 + 300*x^3 + 543*x^4 + 472*x^5 + 288*x^6) / (1 - 10*x + x^2 - 236*x^3 - 270*x^4 - 945*x^5 - 532*x^6 - 576*x^7). - _Colin Barker_, Jun 04 2018
%e A203095 Some solutions for n=5:
%e A203095 ..3..3....0..3....1..1....3..2....1..3....0..3....0..0....1..3....3..0....0..0
%e A203095 ..1..1....3..3....0..1....3..1....2..3....1..3....3..0....3..3....3..3....1..2
%e A203095 ..0..3....2..1....1..1....1..2....1..3....1..1....3..1....3..2....0..3....0..3
%e A203095 ..1..3....1..2....3..2....0..2....2..2....0..2....2..0....2..2....2..1....3..3
%e A203095 ..1..2....1..2....3..0....0..0....1..1....3..3....2..2....2..0....2..2....1..0
%Y A203095 Cf. A203101.
%K A203095 nonn
%O A203095 1,1
%A A203095 _R. H. Hardin_, Dec 29 2011