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A340928 Least image of A001222 applied to the prime indices of n. 1
0, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 1, 0, 3, 0, 1, 0, 1, 0, 2, 0, 1, 0, 2, 0, 2, 0, 1, 0, 4, 0, 1, 0, 1, 0, 1, 0, 3, 0, 1, 0, 1, 0, 1, 0, 1, 0, 3, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 1, 0, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,7
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
EXAMPLE
The prime indices of 4277 are {4,6,15} with images {2,2,2}, so a(4277) = 2.
The prime indices of 8303 are {8,8,9} with images {3,3,2}, so a(8303) = 2.
MATHEMATICA
Table[If[n==1, 0, Min@@PrimeOmega/@PrimePi/@First/@FactorInteger[n]], {n, 100}]
CROSSREFS
Positions of 0's are A000079.
Positions of first appearances are A033844.
The version for maximum is A340691.
A003963 multiplies together the prime indices.
A026794 counts partitions by sum and minimum.
A056239 adds up the prime indices.
A061395 selects the greatest prime index.
A112798 lists the prime indices of each positive integer.
Sequence in context: A133565 A239704 A168570 * A355742 A267860 A325488
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jan 28 2021
STATUS
approved

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Last modified March 28 16:34 EDT 2024. Contains 371254 sequences. (Running on oeis4.)