cp's OEIS Frontend

A240756 Number of n X 2 0..3 arrays with no element equal to one plus the sum of elements to its left or zero plus the sum of 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 A240756 #8 Oct 29 2018 05:19:24
%S A240756 5,6,12,16,16,35,35,36,65,83,102,172,191,230,381,458,576,905,1064,
%T A240756 1362,2090,2514,3267,4869,5894,7740,11297,13853,18318,26249,32499,
%U A240756 43165,60950,76216,101501,141589,178559,238124,328924,418014,557746,764306,977771
%N A240756 Number of n X 2 0..3 arrays with no element equal to one plus the sum of elements to its left or zero plus the sum of 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.
%H A240756 R. H. Hardin, <a href="/A240756/b240756.txt">Table of n, a(n) for n = 1..210</a>
%F A240756 Empirical: a(n) = 3*a(n-3) + a(n-5) - 2*a(n-8) - 4*a(n-9) - a(n-11) + 2*a(n-14) for n>17.
%F A240756 Empirical g.f.: x*(5 + 6*x + 12*x^2 + x^3 - 2*x^4 - 6*x^5 - 19*x^6 - 24*x^7 - 46*x^8 - 6*x^9 + 7*x^10 + 27*x^11 + 8*x^12 + 5*x^13 - 2*x^14 - x^15 - x^16) / ((1 + x)*(1 - x + x^2)*(1 - x^2 - x^3)*(1 - 2*x^3)*(1 + x^2 - x^3 + x^4 - x^5)). - _Colin Barker_, Oct 29 2018
%e A240756 Some solutions for n=4:
%e A240756 ..3..1....3..3....3..3....3..3....3..1....2..2....3..3....3..1....2..2....3..1
%e A240756 ..2..2....2..1....2..2....2..1....2..2....3..1....2..1....2..2....3..1....2..2
%e A240756 ..3..1....3..1....3..3....3..3....3..1....3..2....3..3....3..1....3..1....3..1
%e A240756 ..2..2....2..2....2..2....2..1....2..1....3..2....2..2....3..1....2..2....3..2
%Y A240756 Column 2 of A240760.
%K A240756 nonn
%O A240756 1,1
%A A240756 _R. H. Hardin_, Apr 12 2014