A319181 Numbers that are not perfect powers but whose prime indices have a common divisor > 1.

3, 5, 7, 11, 13, 17, 19, 21, 23, 29, 31, 37, 39, 41, 43, 47, 53, 57, 59, 61, 63, 65, 67, 71, 73, 79, 83, 87, 89, 91, 97, 101, 103, 107, 109, 111, 113, 115, 117, 127, 129, 131, 133, 137, 139, 147, 149, 151, 157, 159, 163, 167, 171, 173, 179, 181, 183, 185, 189

Offset

1,1

Comments

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

Links

Table of n, a(n) for n=1..59.

Example

The sequence of integer partitions whose Heinz numbers are in the sequence begins: (2), (3), (4), (5), (6), (7), (8), (4,2), (9), (10), (11), (12), (6,2), (13), (14), (15), (16), (8,2), (17), (18), (4,2,2), (6,3).

Mathematica

Select[Range[1000], And[GCD@@PrimePi/@FactorInteger[#][[All, 1]]>1, GCD@@FactorInteger[#][[All, 2]]==1]&]

Crossrefs

Cf. A007916, A056239, A072774, A289509, A298748, A319161, A319163, A319165, A319179, A319180.

Sequence in context: A319801 A339907 A255602 * A318718 A118749 A367227

Adjacent sequences: A319178 A319179 A319180 * A319182 A319183 A319184

Keyword

nonn

Author

Gus Wiseman, Sep 12 2018

Status

approved