OFFSET
1,1
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.
EXAMPLE
The terms together with their prime indices begin:
13: {6}
15: {2,3}
26: {1,6}
29: {10}
30: {1,2,3}
33: {2,5}
35: {3,4}
37: {12}
39: {2,6}
43: {14}
45: {2,2,3}
47: {15}
51: {2,7}
52: {1,1,6}
55: {3,5}
58: {1,10}
60: {1,1,2,3}
MATHEMATICA
Select[Range[100], 2==PrimeNu[Times @@ PrimePi/@First/@If[#==1, {}, FactorInteger[#]]]&]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Mar 21 2024
STATUS
approved