2,2

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

I. Jensen, A transfer matrix approach to the enumeration of plane meanders. J. Phys. A 33, 5953-5963 (2000).

I. Jensen and A. J. Guttmann, Critical exponents of plane meanders. J. Phys. A 33, L187-L192 (2000).

J. E. Koehler, Folding a strip of stamps, J. Combin. Theory, 5 (1968), 135-152.

W. F. Lunnon, A map-folding problem, Math. Comp. 22 (1968), 193-199.

J. Touchard, Contributions a` l'e'tude du proble`me des timbres postes, Canad. J. Math., 2 (1950), 385-398.

M. B. Wells, Elements of Combinatorial Computing. Pergamon, Oxford, 1971, p. 238.

P. Di Francesco, O. Golinelli and E. Guitter, Meanders: a direct enumeration approach, Nucl. Phys. B 482 [ FS ] (1996) 497-535.

Index entries for sequences obtained by enumerating foldings

I. Jensen, Home page

Equals (1/2)*A000682 (for n >= 2).

Sequence in context: A115523 A010843 A084075 this_sequence A032124 A000669 A004114

Adjacent sequences: A000557 A000558 A000559 this_sequence A000561 A000562 A000563

nonn,nice

N. J. A. Sloane (njas(AT)research.att.com), legendre(AT)biologie.ens.fr (Stephane LEGENDRE)

Computed to n = 45 by Iwan Jensen - see link in A000682.