cp's OEIS Frontend

A269272 Number of n X 4 0..3 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling three exactly once.

%I A269272 #10 Jan 20 2019 23:18:13
%S A269272 108,13896,1104264,74853576,4684312584,279339197256,16128206816904,
%T A269272 909870855444936,50443519266217224,2758864964165996616,
%U A269272 149253876730080113544,8002845140585293252296,425920265748436386105864
%N A269272 Number of n X 4 0..3 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling three exactly once.
%H A269272 R. H. Hardin, <a href="/A269272/b269272.txt">Table of n, a(n) for n = 1..210</a>
%F A269272 Empirical: a(n) = 98*a(n-1) - 2401*a(n-2) for n > 3.
%F A269272 Conjectures from _Colin Barker_, Jan 20 2019: (Start)
%F A269272 G.f.: 36*x*(3 + 92*x + 49*x^2) / (1 - 49*x)^2.
%F A269272 a(n) = 72 * 49^(n-2) * (120*n-47) for n>1.
%F A269272 (End)
%e A269272 Some solutions for n=2:
%e A269272   3 2 2 0    1 1 0 0    3 0 2 3    0 2 0 3    2 2 3 2
%e A269272   2 2 3 2    1 3 2 0    2 0 1 0    2 2 2 3    0 2 3 0
%Y A269272 Column 4 of A269276.
%K A269272 nonn
%O A269272 1,1
%A A269272 _R. H. Hardin_, Feb 21 2016