OFFSET
1,2
COMMENTS
A prime index of n is a number m such that prime(m) divides n.
EXAMPLE
The sequence of integer partitions whose Heinz numbers are in the sequence begins: (), (21), (211), (41), (32), (221), (42), (2111), (61), (411), (321), (43), (2211), (81), (62), (421), (322), (21111).
MATHEMATICA
Select[Range[100], GCD@@(PrimePi/@FactorInteger[#][[All, 1]]+1)==1&]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Sep 06 2018
STATUS
approved