A318981 Numbers whose prime indices plus 1 are relatively prime.

1, 6, 12, 14, 15, 18, 21, 24, 26, 28, 30, 35, 36, 38, 39, 42, 45, 48, 51, 52, 54, 56, 58, 60, 63, 65, 66, 69, 70, 72, 74, 75, 76, 77, 78, 84, 86, 87, 90, 91, 95, 96, 98, 102, 104, 105, 106, 108, 111, 112, 114, 116, 117, 119, 120, 122, 123, 126, 130, 132, 133

Offset: 1

Author

Gus Wiseman, Sep 06 2018

Keywords

• nonn

Comments

A prime index of n is a number m such that prime(m) divides n.

Examples

			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).
		

Crossrefs

Cf. A000837, A007359, A018783, A281116, A289508, A289509, A318978, A318980.

Programs

Mathematica

Select[Range[100],GCD@@(PrimePi/@FactorInteger[#][[All,1]]+1)==1&]