%I
%S 70,2735,58898,1091036,19105020,325333429,5451265872,90406374528,
%T 1488870622780,24396922947484,398282413965566,6483402596528564,
%U 105301980143117156,1707201970861977822,27637076220888829232
%N Number of 0..3 arrays of length 2*n+3 with sum less than 3*n in any length 2n subsequence (=less than 50% duty cycle)
%C Row 4 of A213464
%H R. H. Hardin, <a href="/A213468/b213468.txt">Table of n, a(n) for n = 1..210</a>
%e Some solutions for n=3
%e ..0....2....2....1....0....2....0....0....3....1....1....0....0....0....1....3
%e ..2....3....2....0....0....0....2....2....1....2....3....0....2....2....3....1
%e ..1....1....0....3....2....1....1....1....1....3....0....0....0....2....3....0
%e ..0....2....0....0....0....2....2....2....0....0....1....2....0....0....0....0
%e ..0....0....0....0....0....1....0....0....0....0....1....1....0....0....1....2
%e ..2....0....3....3....0....0....0....2....3....1....2....0....3....2....0....0
%e ..3....0....0....0....1....0....1....1....0....0....1....0....2....1....1....1
%e ..1....3....0....1....2....2....3....2....3....0....0....1....0....3....0....0
%e ..1....0....2....1....3....2....2....1....2....3....0....1....2....2....3....3
%K nonn
%O 1,1
%A _R. H. Hardin_ Jun 12 2012
|