cp's OEIS Frontend

A240154 Number of 2Xn 0..3 arrays with no element equal to one plus the sum of elements to its left or one plus the sum of the elements above it or one 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 A240154 #6 Jun 02 2025 09:40:51
%S A240154 3,5,8,19,36,57,120,218,377,758,1366,2451,4815,8678,15839,30594,55356,
%T A240154 102004,194522,353711,655297,1238182,2261878,4202427,7889648,14469040,
%U A240154 26917836,50315864,92567160,172279431,321102231,592194036,1102055156
%N A240154 Number of 2Xn 0..3 arrays with no element equal to one plus the sum of elements to its left or one plus the sum of the elements above it or one 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 A240154 Row 2 of A240153
%H A240154 R. H. Hardin, <a href="/A240154/b240154.txt">Table of n, a(n) for n = 1..210</a>
%F A240154 Empirical: a(n) = a(n-2) +8*a(n-3) -5*a(n-5) -18*a(n-6) +a(n-7) +10*a(n-8) +16*a(n-9) -5*a(n-10) -10*a(n-11) +a(n-12) +6*a(n-13) -2*a(n-14) -6*a(n-15) -a(n-16) +6*a(n-17) for n>19
%e A240154 Some solutions for n=4
%e A240154 ..3..2..3..2....2..2..3..3....3..2..3..3....2..2..3..3....2..2..3..2
%e A240154 ..3..2..1..1....0..0..2..1....3..1..2..2....0..2..1..1....0..2..1..1
%K A240154 nonn
%O A240154 1,1
%A A240154 _R. H. Hardin_, Apr 02 2014