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A133923 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)). 1
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; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

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.

LINKS

Table of n, a(n) for n=1..100.

PROG

(MIT Scheme:) (define (A133923 n) (cond ((< n 2) n) ((even? (A133923 (-1+ n))) (/ (A133923 (-1+ n)) 2)) (else (A000005 (* n (A133923 (-1+ n)))))))

CROSSREFS

Cf. A000005.

Sequence in context: A229287 A286539 A004741 * A125158 A273823 A112384

Adjacent sequences:  A133920 A133921 A133922 * A133924 A133925 A133926

KEYWORD

nonn

AUTHOR

Ctibor O. Zizka, Jan 07 2008

EXTENSIONS

Edited, corrected, extended and Scheme-code added by Antti Karttunen, Oct 05 2009

STATUS

approved

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Last modified July 24 04:08 EDT 2019. Contains 325290 sequences. (Running on oeis4.)