%I A077014
%S A077014 2,1,2,2,6,8,28,42,162,262,1076,1828,7852,13820,61388,110954,505878,933458,
%T A077014 4345660,8152860,38608380,73424650,352686780,678390116,3298016912,6405031050,
%U A077014 31461151108,61606881612,305327366988,602188541928,3007925909860,5969806669034
%N A077014 Number of ways that a directed line (or river) that starts in the South 
               can cross an East-West road n times.
%C A077014 The difference between this and A005316 is that here the river can also 
               end up in the South-West. In A005316 it was required to end up in 
               the North-East or South-East.
%C A077014 Or, number of ways that an undirected line that starts and ends anywhere 
               can cross an East-West road n times.
%F A077014 Equals A005316(n) if n odd, or 2*A005316(n) if n even (because then each 
               solution to A005316 can be reflected in a vertical mirror to give 
               another solution).
%Y A077014 Sequence in context: A054706 A081727 A000020 this_sequence A093655 A023140 
               A145859
%Y A077014 Adjacent sequences: A077011 A077012 A077013 this_sequence A077015 A077016 
               A077017
%K A077014 nonn
%O A077014 0,1
%A A077014 N. J. A. Sloane (njas(AT)research.att.com) and Jon Wild (wild(AT)music.mcgill.ca), 
               Nov 29 2002