%I M0840 #26 Jun 28 2017 15:17:07
%S 1,1,2,3,7,14,36,81,221,538,1530,3926,11510,30694,92114,252939,773259,
%T 2172830,6743122,19304190,60658606,176343390,559952824,1649008456,
%U 5283239596,15730575554,50789908772,152663683494
%N Number of meanders in which first bridge is 3.
%D S. K. Lando and A. K. Zvonkin "Plane and projective meanders", Séries Formelles et Combinatoire Algébrique. Laboratoire Bordelais de Recherche Informatique, Université Bordeaux I, 1991, pp. 287-303.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H S. K. Lando and A. K. Zvonkin , <a href="/A005316/a005316_1.pdf">Plane and projective meanders</a>, Séries Formelles et Combinatoire Algébrique. Laboratoire Bordelais de Recherche Informatique, Université Bordeaux I, 1991, pp. 287-303. (Annotated scanned copy)
%Y Cf. A259974, A005316.
%K nonn
%O 3,3
%A _Simon Plouffe_
%E a(19)-a(30) from _Andrew Howroyd_, Dec 15 2015