OFFSET
1,4
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
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
The prime indices of 6776 are {1,1,1,4,5,5}, four of which {1,1,1,4} divide 6776, so a(6776) = 4.
MATHEMATICA
Table[Total[Cases[If[n==1, {}, FactorInteger[n]], {p_, k_}:>k/; Divisible[n, PrimePi[p]]]], {n, 100}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Mar 18 2019
STATUS
approved