%I A000560 M1420 N0557
%S A000560 1,2,5,12,33,87,252,703,2105,6099,18689,55639,173423,526937,1664094,
%T A000560 5137233,16393315,51255709,164951529,521138861,1688959630,
%U A000560 5382512216,17547919924,56335234064,184596351277,596362337295,1962723402375
%N A000560 Number of ways of folding a strip of n labeled stamps.
%D A000560 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A000560 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%D A000560 I. Jensen, A transfer matrix approach to the enumeration of plane meanders. 
               J. Phys. A 33, 5953-5963 (2000).
%D A000560 I. Jensen and A. J. Guttmann, Critical exponents of plane meanders. J. 
               Phys. A 33, L187-L192 (2000).
%D A000560 J. E. Koehler, Folding a strip of stamps, J. Combin. Theory, 5 (1968), 
               135-152.
%D A000560 W. F. Lunnon, A map-folding problem, Math. Comp. 22 (1968), 193-199.
%D A000560 J. Touchard, Contributions a` l'e'tude du proble`me des timbres postes, 
               Canad. J. Math., 2 (1950), 385-398.
%D A000560 M. B. Wells, Elements of Combinatorial Computing. Pergamon, Oxford, 1971, 
               p. 238.
%H A000560 P. Di Francesco, O. Golinelli and E. Guitter, <a href="http://arXiv.org/
               abs/hep-th/9607039">Meanders: a direct enumeration approach</a>, 
               Nucl. Phys. B 482 [ FS ] (1996) 497-535.
%H A000560 <a href="Sindx_Fo.html#fold">Index entries for sequences obtained by 
               enumerating foldings</a>
%H A000560 I. Jensen, <a href="http://www.ms.unimelb.edu.au/~iwan/">Home page</a>
%Y A000560 Equals (1/2)*A000682 (for n >= 2).
%Y A000560 Sequence in context: A115523 A010843 A084075 this_sequence A032124 A000669 
               A004114
%Y A000560 Adjacent sequences: A000557 A000558 A000559 this_sequence A000561 A000562 
               A000563
%K A000560 nonn,nice
%O A000560 2,2
%A A000560 N. J. A. Sloane (njas(AT)research.att.com), legendre(AT)biologie.ens.fr 
               (Stephane LEGENDRE)
%E A000560 Computed to n = 45 by Iwan Jensen - see link in A000682.