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A000560 Number of ways of folding a strip of n labeled stamps.
(Formerly M1420 N0557)
6
1, 2, 5, 12, 33, 87, 252, 703, 2105, 6099, 18689, 55639, 173423, 526937, 1664094, 5137233, 16393315, 51255709, 164951529, 521138861, 1688959630, 5382512216, 17547919924, 56335234064, 184596351277, 596362337295, 1962723402375 (list; graph; refs; listen; history; internal format)
OFFSET

2,2

REFERENCES

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.

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

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

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.

LINKS

T. D. Noe, Table of n, a(n) for n = 2..44 (derived from A000682)

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

I. Jensen, Home page

Index entries for sequences obtained by enumerating foldings

CROSSREFS

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

Sequence in context: A176336 A010843 A084075 * A032124 A000669 A191769

Adjacent sequences:  A000557 A000558 A000559 * A000561 A000562 A000563

KEYWORD

nonn,nice

AUTHOR

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

EXTENSIONS

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

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Last modified February 15 23:21 EST 2012. Contains 205860 sequences.