cp's OEIS Frontend

A241307 Number of 2Xn 0..3 arrays with no element equal to zero plus the sum of elements to its left or one plus the sum of the elements above it or zero plus the sum of the elements diagonally to its northwest or zero plus the sum of the elements antidiagonally to its northeast, modulo 4.

%I A241307 #6 Jun 02 2025 10:05:15
%S A241307 5,6,15,25,40,89,121,237,390,682,1250,2069,3698,6352,11013,19408,
%T A241307 33478,58524,101542,176797,307761,535313,932344,1620570,2821554,
%U A241307 4908976,8540842,14866293,25861744,45006289,78311151,136266311,237120535
%N A241307 Number of 2Xn 0..3 arrays with no element equal to zero plus the sum of elements to its left or one plus the sum of the elements above it or zero plus the sum of the elements diagonally to its northwest or zero plus the sum of the elements antidiagonally to its northeast, modulo 4.
%C A241307 Row 2 of A241306
%H A241307 R. H. Hardin, <a href="/A241307/b241307.txt">Table of n, a(n) for n = 1..210</a>
%F A241307 Empirical: a(n) = 2*a(n-2) +3*a(n-3) -a(n-4) -a(n-5) +2*a(n-6) -10*a(n-8) -7*a(n-9) +8*a(n-10) +5*a(n-11) -3*a(n-12) -7*a(n-13) +7*a(n-14) for n>20
%e A241307 Some solutions for n=4
%e A241307 ..3..2..3..2....3..2..3..3....3..2..3..3....2..3..3..2....3..2..2..2
%e A241307 ..3..1..1..2....3..0..1..2....3..1..1..2....2..1..1..2....3..0..0..1
%K A241307 nonn
%O A241307 1,1
%A A241307 _R. H. Hardin_, Apr 18 2014