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A175064 a(1) = 1; for n >= 2, a(n) = number of ways h to write the n-th perfect power A001597(n) as m^k with m >= 2 and k >= 1. 9
1, 2, 2, 2, 3, 2, 2, 2, 2, 2, 4, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 4, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 3, 2, 4, 2, 2, 2, 2, 2, 4, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 2, 2, 2, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Perfect powers with first occurrence of h >= 2: 4, 16, 64, 65536, 4096, ...

LINKS

Table of n, a(n) for n=1..86.

FORMULA

a(n) = A000005(A253641(A001597(n))) = A253642(n)+1. - M. F. Hasler, Jan 25 2015

EXAMPLE

For n = 11: A001597(11) = 64; there are 4 ways to write 64 as m^k: 64^1 = 8^2 = 4^3 = 2^6.

CROSSREFS

Cf. A253641, A253642, A000005, A001597.

Sequence in context: A193990 A089367 A130192 * A104564 A160764 A156384

Adjacent sequences:  A175061 A175062 A175063 * A175065 A175066 A175067

KEYWORD

nonn

AUTHOR

Jaroslav Krizek, Jan 23 2010

EXTENSIONS

Extended by T. D. Noe, Apr 21 2011

Definition clarified by Jonathan Sondow, Nov 30 2012

STATUS

approved

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Last modified April 16 05:26 EDT 2021. Contains 343030 sequences. (Running on oeis4.)