cp's OEIS Frontend

A297220 Number of n X 4 0..1 arrays with every 1 horizontally or antidiagonally adjacent to 1 neighboring 1s.

%I A297220 #8 Feb 26 2019 12:05:47
%S A297220 4,16,57,207,751,2720,9861,35741,129540,469528,1701805,6168220,
%T A297220 22356839,81032722,293704534,1064537220,3858433620,13984959985,
%U A297220 50688731051,183722188635,665904273716,2413581640617,8748068704189,31707527421628
%N A297220 Number of n X 4 0..1 arrays with every 1 horizontally or antidiagonally adjacent to 1 neighboring 1s.
%H A297220 R. H. Hardin, <a href="/A297220/b297220.txt">Table of n, a(n) for n = 1..210</a>
%F A297220 Empirical: a(n) = a(n-1) + 6*a(n-2) + 11*a(n-3) + 6*a(n-4) + a(n-5).
%F A297220 Empirical g.f.: x*(2 + x)^2*(1 + 2*x + 2*x^2) / (1 - x - 6*x^2 - 11*x^3 - 6*x^4 - x^5). - _Colin Barker_, Feb 26 2019
%e A297220 Some solutions for n=7:
%e A297220 ..0..0..1..1. .0..0..0..0. .0..0..0..0. .0..0..1..0. .0..1..0..0
%e A297220 ..0..0..0..0. .0..0..0..0. .0..0..0..0. .0..1..0..0. .1..0..0..0
%e A297220 ..1..1..0..0. .0..1..0..1. .0..1..0..0. .0..1..0..1. .1..1..0..1
%e A297220 ..0..0..1..0. .1..0..1..0. .1..0..0..0. .1..0..1..0. .0..0..1..0
%e A297220 ..0..1..0..0. .0..0..0..0. .1..1..0..0. .0..0..1..1. .0..0..1..1
%e A297220 ..0..1..0..1. .0..0..0..0. .0..1..0..1. .0..0..0..0. .0..0..0..0
%e A297220 ..1..0..1..0. .0..0..1..1. .1..0..1..0. .1..1..0..0. .1..1..0..0
%Y A297220 Column 4 of A297224.
%K A297220 nonn
%O A297220 1,1
%A A297220 _R. H. Hardin_, Dec 27 2017