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Search: id:A004738
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| A004738 |
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Concatenation of sequences (1,2,..,n-1,n,n-1,..,2) for n >= 2. |
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+0
7
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| 1, 2, 1, 2, 3, 2, 1, 2, 3, 4, 3, 2, 1, 2, 3, 4, 5, 4, 3, 2, 1, 2, 3, 4, 5, 6, 5, 4, 3, 2, 1, 2, 3, 4, 5, 6, 7, 6, 5, 4, 3, 2, 1, 2, 3, 4, 5, 6, 7, 8, 7, 6, 5, 4, 3, 2, 1, 2, 3, 4, 5, 6, 7, 8, 9, 8, 7, 6, 5, 4, 3, 2, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 10, 9
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Also called Smarandache Decrescendo Pyramidal Sequence.
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REFERENCES
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F. Smarandache, "Collected Papers", Vol. II, Tempus Publ. Hse., Bucharest, 1996; F. Smarandache, "Numerical Sequences", University of Craiova, 1975; [ See Arizona State University, Special Collection, Tempe, AZ, USA ].
F. Smarandache, Sequences of Numbers Involved in Unsolved Problems, Hexis, Phoenix, 2006.
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LINKS
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M. L. Perez et al., eds., Smarandache Notions Journal
F. Smarandache, Collected Papers, Vol. II
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
F. Smarandache, Sequences of Numbers Involved in Unsolved Problems.
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FORMULA
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a(n)= floor(sqrt(n)+1/2)+1-abs(n-1-(floor(sqrt(n)+1/2))^2) - Benoit Cloitre (benoit7848c(AT)orange.fr), Feb 08 2003
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PROGRAM
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(PARI) a(n)= floor(sqrt(n)+1/2)+1-abs(n-1-(floor(sqrt(n)+1/2)-1/2)^2)
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CROSSREFS
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Cf. A004737, A004739.
Sequence in context: A089280 A100661 A088696 this_sequence A043554 A005811 A008342
Adjacent sequences: A004735 A004736 A004737 this_sequence A004739 A004740 A004741
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KEYWORD
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nonn,easy
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AUTHOR
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R. Muller
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EXTENSIONS
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More terms from Patrick De Geest (pdg(AT)worldofnumbers.com), Jun 15 1998.
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