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A101436 Number of exponents in prime factorization of n which are primes. +0
2
0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 1, 2, 0, 0, 0, 1, 0 (list; graph; listen)
OFFSET

1,36

COMMENT

First occurrence of k: 1,4,36,900,44100 (A061742). - Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 25 2005

LINKS

Leroy Quet, Home Page (listed in lieu of email address)

EXAMPLE

36 = 2^2 *3^2. Since 2 is a prime and occurs twice as an exponent in the prime factorization of 36, a(36) = 2.

MATHEMATICA

f[n_] := Length[ Select[ Flatten[ Table[ #[[2]], {1}] & /@ FactorInteger[n]], PrimeQ[ # ] &]]; Table[ f[n], {n, 105}] (from Robert G. Wilson v Jan 25 2005)

CROSSREFS

Adjacent sequences: A101433 A101434 A101435 this_sequence A101437 A101438 A101439

Sequence in context: A133698 A093956 A160383 this_sequence A056170 A059483 A067618

KEYWORD

nonn

AUTHOR

Leroy Quet, Jan 18 2005

EXTENSIONS

More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 25 2005

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Last modified November 8 20:39 EST 2009. Contains 166234 sequences.


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