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A133923 2-divided number of divisors of n*a(n-1). +0
1
1, 1, 2, 1, 3, 4, 2, 1, 4, 2, 1, 2, 1, 4, 2, 1, 2, 1, 2, 1, 4, 2, 1, 8, 4, 2, 1, 6, 3, 12, 6, 3, 6, 3, 8, 4, 2, 1, 2, 1, 2, 1, 2, 1, 6, 3, 4, 2, 1, 6, 3, 12, 6, 3, 8, 4, 2, 1, 2, 1, 2, 6, 3, 16, 8, 4, 2, 1 (list; graph; listen)
OFFSET

1,3

COMMENT

Let A, B, C are integers. We have a class of sequences a(n)= d(A*a(n-1)+B) if a(n-1) is not divisible by C, else a(n)= a(n-1)/C.

FORMULA

a(n)= d(n*a(n-1)) if a(n-1)is not divisible by 2 else a(n)= a(n-1)/2 . d(n*a(n-1)) is the number of divisors of n*a(n-1)

CROSSREFS

Cf. A000005.

Sequence in context: A049400 A106382 A004741 this_sequence A145034 A125158 A112384

Adjacent sequences: A133920 A133921 A133922 this_sequence A133924 A133925 A133926

KEYWORD

nonn,uned

AUTHOR

Ctibor O. ZIZKA (ctibor.zizka(AT)seznam.cz), Jan 07 2008

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Last modified December 4 21:35 EST 2008. Contains 151309 sequences.


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