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A122375 Number of distinct prime factors of the smallest number with exactly n divisors. 5
0, 1, 1, 2, 1, 2, 1, 2, 2, 2, 1, 3, 1, 2, 2, 3, 1, 3, 1, 3, 2, 2, 1, 3, 2, 2, 3, 3, 1, 3, 1, 4, 2, 2, 2, 4, 1, 2, 2, 4, 1, 3, 1, 3, 3, 2, 1, 4, 2, 3, 2, 3, 1, 4, 2, 4, 2, 2, 1, 4, 1, 2, 3, 4, 2, 3, 1, 3, 2, 3, 1, 4, 1, 2, 3, 3, 2, 3, 1, 4, 4, 2, 1, 4, 2, 2, 2, 4, 1, 4, 2, 3, 2, 2, 2, 5, 1, 3, 3, 4, 1, 3, 1, 4, 3 (list; graph; refs; listen; history; internal format)
OFFSET

1,4

COMMENTS

a(n)=1 iff n is prime.

FORMULA

a(n) = omega(A005179(n)), where omega(n) = A001221(n).

a(n) = A001221(A130279(n)). - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), May 21 2007

CROSSREFS

Cf. A038457.

Sequence in context: A056171 A076755 A106490 * A038548 A068108 A113309

Adjacent sequences:  A122372 A122373 A122374 * A122376 A122377 A122378

KEYWORD

nonn

AUTHOR

Lekraj Beedassy (blekraj(AT)yahoo.com), Aug 30 2006

EXTENSIONS

Edited and extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Sep 11 2006

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Last modified February 16 11:47 EST 2012. Contains 205907 sequences.