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A078570 Number of distinct prime factors of the average of n-th twin prime pair. 4
1, 2, 2, 2, 3, 3, 3, 2, 3, 2, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 3, 4, 2, 4, 3, 4, 3, 3, 3, 4, 3, 3, 3, 4, 3, 4, 3, 4, 3, 4, 2, 4, 3, 4, 4, 4, 4, 3, 4, 3, 3, 3, 3, 3, 4, 3, 3, 3, 4, 4, 3, 3, 3, 3, 3, 4, 4, 3, 3, 5, 4, 3, 4, 2, 3, 3, 3, 5, 4, 3, 4, 3, 4, 3, 3, 3, 4, 4, 4, 3, 4, 3, 3, 3, 4, 3, 3, 3, 3, 4, 3, 3, 4, 4, 4 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

a(n)=A001221(A014574(n)).

EXAMPLE

12-th twin prime pair = (A001359(12), A006512(12)) = (149,151), hence A014574(12) = 150 = 2*3*5*5, therefore a(12) = 3.

CROSSREFS

Cf. A078571, A078572.

Sequence in context: A181611 A064740 A080967 * A037179 A127971 A192688

Adjacent sequences:  A078567 A078568 A078569 * A078571 A078572 A078573

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Nov 29 2002

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Last modified February 16 03:44 EST 2012. Contains 205860 sequences.