OFFSET
1,1
COMMENTS
EXAMPLE
The terms together with their prime indices begin:
2: {1} 19: {8} 39: {2,6}
3: {2} 21: {2,4} 41: {13}
4: {1,1} 22: {1,5} 43: {14}
5: {3} 23: {9} 46: {1,9}
7: {4} 25: {3,3} 47: {15}
8: {1,1,1} 27: {2,2,2} 49: {4,4}
9: {2,2} 29: {10} 53: {16}
10: {1,3} 30: {1,2,3} 55: {3,5}
11: {5} 31: {11} 57: {2,8}
13: {6} 32: {1,1,1,1,1} 59: {17}
16: {1,1,1,1} 34: {1,7} 61: {18}
17: {7} 37: {12} 62: {1,11}
MATHEMATICA
prix[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];
prisig[n_]:=If[n==1, {}, Last/@FactorInteger[n]];
Select[Range[100], IntegerQ[Mean[prix[#]]]&&IntegerQ[Mean[prisig[#]]]&]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jan 25 2023
STATUS
approved