

A001415


Number of ways of folding a 2 X n strip of stamps.
(Formerly M1891 N0745)


0



1, 2, 8, 60, 320, 1980, 10512, 60788, 320896, 1787904, 9381840, 51081844, 266680992, 1429703548, 7432424160, 39409195740, 204150606976, 1073644675448, 5545305620064
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OFFSET

0,2


COMMENTS

a(n), called G(n,2), is known to be divisible by 4n for n >= 2.  Fred Lunnon, Dec 08 2013


REFERENCES

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).


LINKS

Table of n, a(n) for n=0..18.
R. Dickau, Map Folding
R. Dickau, Folding a 2xn Sheet of Labeled Stamps, Wolfram Demonstrations Project
W. F. Lunnon, Multidimensional mapfolding, Computer Journal 14 1971 7580.
Eric Weisstein's World of Mathematics, Map Folding
Index entries for sequences obtained by enumerating foldings


CROSSREFS

Sequence in context: A295502 A196076 A027278 * A305730 A053871 A208124
Adjacent sequences: A001412 A001413 A001414 * A001416 A001417 A001418


KEYWORD

nonn,more


AUTHOR

N. J. A. Sloane.


EXTENSIONS

a(12)a(18) from Fred Lunnon, Dec 08 2013


STATUS

approved



