cp's OEIS Frontend

A269285 Number of n X 4 0..3 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling three no more than once.

%I A269285 #8 Jan 21 2019 06:27:57
%S A269285 216,19188,1363572,87559668,5306911092,309846524148,17623065834612,
%T A269285 983118947312628,54032675767734132,2934733632740325108,
%U A269285 157871441490222209652,8425105813832255961588,446611038737537558861172
%N A269285 Number of n X 4 0..3 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling three no more than once.
%H A269285 R. H. Hardin, <a href="/A269285/b269285.txt">Table of n, a(n) for n = 1..210</a>
%F A269285 Empirical: a(n) = 98*a(n-1) - 2401*a(n-2) for n>3.
%F A269285 Conjectures from _Colin Barker_, Jan 21 2019: (Start)
%F A269285 G.f.: 36*x*(1 - x)*(6 - 49*x) / (1 - 49*x)^2.
%F A269285 a(n) = 36 * (49^(n-2) * (240*n+53)) for n>1.
%F A269285 (End)
%e A269285 Some solutions for n=2:
%e A269285 ..3..0..2..0. .3..1..1..3. .1..3..3..2. .3..2..0..2. .0..0..2..3
%e A269285 ..2..0..2..3. .1..3..2..1. .3..3..3..0. .3..0..2..2. .2..2..2..0
%Y A269285 Column 4 of A269289.
%K A269285 nonn
%O A269285 1,1
%A A269285 _R. H. Hardin_, Feb 21 2016