A302600 1, 2, prime numbers of prime index, and prime numbers of prime index times 2.

1, 2, 3, 5, 6, 10, 11, 17, 22, 31, 34, 41, 59, 62, 67, 82, 83, 109, 118, 127, 134, 157, 166, 179, 191, 211, 218, 241, 254, 277, 283, 314, 331, 353, 358, 367, 382, 401, 422, 431, 461, 482, 509, 547, 554, 563, 566, 587, 599, 617, 662, 706, 709, 734, 739, 773

Offset

1,2

Comments

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

Also squarefree numbers whose prime indices other than 1 are equal prime numbers.

Links

Table of n, a(n) for n=1..56.

Example

Entry A302242 describes a correspondence between positive integers and multiset multisystems. In this case it gives the following sequence of set systems.
01: {}
02: {{}}
03: {{1}}
05: {{2}}
06: {{},{1}}
10: {{},{2}}
11: {{3}}
17: {{4}}
22: {{},{3}}
31: {{5}}
34: {{},{4}}
41: {{6}}
59: {{7}}
62: {{},{5}}
67: {{8}}
82: {{},{6}}
83: {{9}}

Mathematica

Select[Range[1000], SquareFreeQ[#]&&SameQ@@DeleteCases[primeMS[#], 1]&&And@@PrimeQ/@DeleteCases[primeMS[#], 1]&]

Crossrefs

Cf. A000961, A001222, A003963, A005117, A007716, A056239, A275024, A047966, A281113, A296134, A301766, A302242, A302243.

Sequence in context: A130689 A024560 A000039 * A053436 A057546 A339514

Adjacent sequences: A302597 A302598 A302599 * A302601 A302602 A302603

Keyword

nonn

Author

Gus Wiseman, Apr 10 2018

Status

approved