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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

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

Sequence in context: A024326 A133698 A093956 this_sequence A056170 A059483 A067618

Adjacent sequences: A101433 A101434 A101435 this_sequence A101437 A101438 A101439

KEYWORD

nonn

AUTHOR

Leroy Quet (q1qq2qqq3qqqq(AT)yahoo.com), 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 30 22:12 EST 2008. Contains 150989 sequences.


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