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A326620 Denominator of the average of the set of distinct prime indices of n. 5
1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 2, 2, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 1, 1, 1, 2, 1, 2, 2, 1, 2, 1, 1, 1, 3, 1, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 2, 1, 2, 1, 2, 1, 1, 1, 1, 1, 1, 2, 3, 1, 1, 2, 3, 1, 2, 1, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 3, 1, 2, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,5

COMMENTS

A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798.

LINKS

Table of n, a(n) for n=2..88.

EXAMPLE

The distinct prime indices of 12 are {1,2}, with average 3/2, so a(12) = 2.

The sequence of fractions begins: 1, 2, 1, 3, 3/2, 4, 1, 2, 2, 5, 3/2, 6, 5/2, 5/2, 1, 7, 3/2, 8, 2, 3, 3, 9, 3/2, 3, 7/2, 2, 5/2, 10, 2.

MATHEMATICA

Table[Denominator[Mean[PrimePi/@First/@FactorInteger[n]]], {n, 2, 100}]

CROSSREFS

Positions of 1's are A326621.

The average of the multiset of prime indices is A326567/A326568.

The average of the multiset of prime factors is A123528/A123529.

The average of the set of distinct prime indices is A326619/A326620.

The average of the set of distinct prime factors is A323171/A323172.

Cf. A001221, A067629, A078174, A078175, A112798, A316413.

Sequence in context: A338411 A326775 A317240 * A305501 A184170 A025919

Adjacent sequences:  A326617 A326618 A326619 * A326621 A326622 A326623

KEYWORD

nonn,frac

AUTHOR

Gus Wiseman, Jul 14 2019

STATUS

approved

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Last modified July 24 23:25 EDT 2021. Contains 346273 sequences. (Running on oeis4.)