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A001415
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Number of ways of folding a 2 X n strip of stamps.
(Formerly M1891 N0745)
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0
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1, 2, 8, 60, 320, 1980, 10512, 60788, 320896, 1787904, 9381840, 51081844, 266680992, 1429703548, 7432424160, 39409195740, 204150606976, 1073644675448, 5545305620064
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OFFSET
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0,2
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COMMENTS
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a(n), called G(n,2), is known to be divisible by 4n for n >= 2. - Fred Lunnon, Dec 08 2013
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REFERENCES
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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).
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LINKS
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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, Multi-dimensional map-folding, Computer Journal 14 1971 75-80.
Eric Weisstein's World of Mathematics, Map Folding
Index entries for sequences obtained by enumerating foldings
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CROSSREFS
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Sequence in context: A295502 A196076 A027278 * A305730 A053871 A208124
Adjacent sequences: A001412 A001413 A001414 * A001416 A001417 A001418
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KEYWORD
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nonn,more
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AUTHOR
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N. J. A. Sloane.
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EXTENSIONS
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a(12)-a(18) from Fred Lunnon, Dec 08 2013
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STATUS
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approved
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