cp's OEIS Frontend

A240322 Number of n X 2 0..3 arrays with no element equal to zero plus the sum of elements to its left or zero plus the sum of elements above it or one plus the sum of the elements diagonally to its northwest, modulo 4.

%I A240322 #9 Oct 27 2018 06:33:19
%S A240322 2,5,17,37,80,213,443,1028,2511,5370,12742,29737,65687,155443,355668,
%T A240322 803696,1883007,4285398,9805203,22760901,51853646,119272787,275149593,
%U A240322 628629688,1447871151,3328934761,7625189365,17555754237,40308328871
%N A240322 Number of n X 2 0..3 arrays with no element equal to zero plus the sum of elements to its left or zero plus the sum of elements above it or one plus the sum of the elements diagonally to its northwest, modulo 4.
%H A240322 R. H. Hardin, <a href="/A240322/b240322.txt">Table of n, a(n) for n = 1..210</a>
%F A240322 Empirical: a(n) = 2*a(n-2) + 10*a(n-3) - a(n-4) - 5*a(n-5) - 15*a(n-6) + a(n-7) + 4*a(n-8) + 2*a(n-9) + 10*a(n-10) + 5*a(n-11) - 6*a(n-13) for n>14.
%F A240322 Empirical g.f.: x*(2 + 5*x + 13*x^2 + 7*x^3 - 2*x^4 - 16*x^5 - 15*x^6 - 3*x^7 + 2*x^8 + 11*x^9 + 13*x^10 + 3*x^11 - 3*x^12 - 4*x^13) / (1 - 2*x^2 - 10*x^3 + x^4 + 5*x^5 + 15*x^6 - x^7 - 4*x^8 - 2*x^9 - 10*x^10 - 5*x^11 + 6*x^13). - _Colin Barker_, Oct 27 2018
%e A240322 Some solutions for n=4:
%e A240322 ..3..2....3..2....3..2....3..2....3..2....2..3....2..3....2..3....2..3....2..3
%e A240322 ..2..1....2..1....2..3....2..1....2..1....3..2....3..0....3..0....3..0....3..0
%e A240322 ..3..1....2..0....3..2....3..2....3..0....2..3....3..2....3..1....2..1....3..1
%e A240322 ..2..1....2..0....2..1....3..2....3..2....2..1....3..2....3..1....2..1....2..3
%Y A240322 Column 2 of A240327.
%K A240322 nonn
%O A240322 1,1
%A A240322 _R. H. Hardin_, Apr 03 2014