|
%I #8 Sep 06 2023 16:20:59
%S 4,23,129,698,3805,20818,113774,621754,3399032,18582965,101593258,
%T 555419633,3036563927,16601366841,90762262155,496211843813,
%U 2712870511114,14831702705726,81087325012785,443317575022163,2423689199017701,13250702601112477,72443743963082659,396061718589309511
%N Number of n X 2 0..3 arrays with no element equal to one plus the sum of elements to its left or two plus the sum of elements above it, modulo 4.
%H R. H. Hardin, <a href="/A239399/b239399.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 9*a(n-1) -28*a(n-2) +74*a(n-3) -181*a(n-4) +236*a(n-5) -261*a(n-6) +234*a(n-7) +200*a(n-8) -279*a(n-9) +104*a(n-10) -268*a(n-11) -36*a(n-12) +156*a(n-13) +104*a(n-14) -32*a(n-15) -16*a(n-16).
%e Some solutions for n=5:
%e ..3..1....0..0....0..3....0..0....3..3....3..3....3..3....3..1....3..1....0..0
%e ..0..0....3..1....3..3....0..3....3..3....0..0....3..3....0..2....0..2....0..0
%e ..2..2....2..2....3..2....0..2....3..2....2..0....2..2....0..2....0..2....0..0
%e ..2..0....2..2....3..1....0..2....0..3....0..3....3..1....2..0....0..0....3..3
%e ..3..2....3..1....2..0....0..0....2..0....0..2....3..1....0..0....0..2....0..0
%Y Column 2 of A239405.
%K nonn
%O 1,1
%A _R. H. Hardin_, Mar 17 2014
| 