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.
A sequence is periodic if its cyclic rotations are not all different.
EXAMPLE
The sequence of terms together with their differences of prime indices begins:
8: (0,0)
16: (0,0,0)
27: (0,0)
30: (1,1)
32: (0,0,0,0)
64: (0,0,0,0,0)
81: (0,0,0)
105: (1,1)
110: (2,2)
125: (0,0)
128: (0,0,0,0,0,0)
180: (0,1,0,1)
210: (1,1,1)
238: (3,3)
243: (0,0,0,0)
256: (0,0,0,0,0,0,0)
273: (2,2)
343: (0,0)
385: (1,1)
450: (1,0,1,0)
MATHEMATICA
primeMS[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];
aperQ[q_]:=Array[RotateRight[q, #1]&, Length[q], 1, UnsameQ];
Select[Range[10000], !aperQ[Differences[primeMS[#]]]&]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Nov 09 2019
STATUS
approved