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Search: id:A126309
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| 0, 0, 0, 1, 0, 1, 1, 1, 3, 0, 1, 1, 1, 3, 1, 2, 1, 1, 3, 3, 3, 3, 8, 0, 1, 1, 1, 3, 1, 2, 1, 1, 3, 3, 3, 3, 8, 1, 2, 2, 2, 5, 1, 2, 1, 1, 3, 3, 3, 3, 8, 3, 6, 3, 3, 7, 3, 3, 3, 8, 8, 8, 8, 8, 22, 0, 1, 1, 1, 3, 1, 2, 1, 1, 3, 3, 3, 3, 8, 1, 2, 2, 2, 5, 1, 2, 1, 1, 3, 3, 3, 3, 8, 3, 6, 3, 3, 7, 3, 3, 3, 8
(list; graph; listen)
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OFFSET
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0,9
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COMMENT
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According to Vaille, the concept of "compression d'un pont" was introduced by Poupard, in "Sur les quasi-points" paper. In effect, the operation removes all the peaks /\ from the Dyck path.
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REFERENCES
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Y. Poupard, Sur les quasi-ponts, Cahiers du Bureau Universitaire de Recherche Operationelle, Cahier no. 32, Paris, 1979, pp. 3-20.
J. Vaill\'{e}, Une Bijection Explicative de Plusieurs Proprietes Remarquables des Ponts, European J. Combin. 18 (1997), no. 1, 117-124.
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FORMULA
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a(n) = A080300(A126308(A014486(n))).
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EXAMPLE
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A014486(4) encodes the Dyck path /\/\/\, of which, when all the peaks are removed, nothing remains, thus a(4)=0. A014486(18) encodes the Dyck path:
....../\
.../\/..\
../......\,
which, after the peaks are removed, results
.../\,
../..\ encoded by A014486(3), thus a(18)=3.
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CROSSREFS
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a(n) = A125985(A126310(A125986(n))).
Sequence in context: A051908 A056614 A092510 this_sequence A048838 A059341 A131802
Adjacent sequences: A126306 A126307 A126308 this_sequence A126310 A126311 A126312
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KEYWORD
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nonn
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AUTHOR
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Antti Karttunen (His-Firstname.His-Surname(AT)gmail.com), Jan 02 2007
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