OFFSET
1,1
COMMENTS
EXAMPLE
The sequence of terms together with their prime indices begins:
2: {1}
4: {1,1}
5: {3}
6: {1,2}
8: {1,1,1}
10: {1,3}
12: {1,1,2}
14: {1,4}
15: {2,3}
16: {1,1,1,1}
17: {7}
18: {1,2,2}
20: {1,1,3}
22: {1,5}
23: {9}
24: {1,1,1,2}
25: {3,3}
26: {1,6}
28: {1,1,4}
30: {1,2,3}
MATHEMATICA
aQ[n_]:=!And@@Cases[If[n==1, {}, FactorInteger[n]], {p_, k_}:>aQ[PrimePi[p]]];
Select[Range[100], aQ]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Mar 10 2019
STATUS
approved