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Search: id:A133923
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| A133923 |
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a(1)=1, and for n>1, a(n) = a(n-1)/2, if a(n-1) is divisible by 2, otherwise a(n) = A000005(n*a(n-1)). |
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| 1, 2, 1, 3, 4, 2, 1, 4, 2, 1, 2, 1, 2, 1, 4, 2, 1, 6, 3, 12, 6, 3, 4, 2, 1, 4, 2, 1, 2, 1, 2, 1, 4, 2, 1, 9, 6, 3, 6, 3, 4, 2, 1, 6, 3, 8, 4, 2, 1, 6, 3, 12, 6, 3, 8, 4, 2, 1, 2, 1, 2, 1, 6, 3, 8, 4, 2, 1, 4, 2, 1, 12, 6, 3, 9, 18, 9, 16, 8, 4, 2, 1, 2, 1, 4, 2, 1, 8, 4, 2, 1, 6, 3, 8, 4, 2, 1, 6, 3, 18
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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The formula could be generalized to a class of sequences as a(n)= A000005(A*a(n-1)+B) if a(n-1) is not divisible by C, else a(n)= a(n-1)/C, where A, B, C are integers. In this case we have A=n, B=0 and C=2.
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PROGRAM
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(MIT Scheme:) (define (A133923 n) (cond ((< n 2) n) ((even? (A133923 (-1+ n))) (/ (A133923 (-1+ n)) 2)) (else (A000005 (* n (A133923 (-1+ n)))))))
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CROSSREFS
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Cf. A000005.
Sequence in context: A049400 A106382 A004741 this_sequence A145034 A125158 A112384
Adjacent sequences: A133920 A133921 A133922 this_sequence A133924 A133925 A133926
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KEYWORD
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nonn
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AUTHOR
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Ctibor O. ZIZKA (ctibor.zizka(AT)seznam.cz), Jan 07 2008
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EXTENSIONS
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Edited, corrected, extended and Scheme-code added by Antti Karttunen (His-Firstname.His-Surname(AT)gmail.com), Oct 05 2009
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