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A324926 Numbers not divisible by any prime indices of their prime indices. 7
1, 2, 4, 5, 8, 11, 16, 17, 22, 23, 25, 31, 32, 34, 41, 44, 47, 55, 59, 62, 64, 67, 73, 82, 83, 85, 88, 97, 103, 109, 115, 118, 121, 124, 125, 127, 128, 134, 137, 149, 157, 164, 166, 167, 176, 179, 187, 191, 194, 197, 205, 211, 218, 227, 233, 235, 236, 241, 242 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A prime index of n is a number m such that prime(m) divides n. For example, the prime indices of 55 are {3,5} with prime indices {{2},{3}}. Since 55 is not divisible by 2 or 3, it belongs to the sequence.

LINKS

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

EXAMPLE

The sequence of multisets of multisets whose MM-numbers (see A302242) belong to the sequence begins:

   1: {}

   2: {{}}

   4: {{},{}}

   5: {{2}}

   8: {{},{},{}}

  11: {{3}}

  16: {{},{},{},{}}

  17: {{4}}

  22: {{},{3}}

  23: {{2,2}}

  25: {{2},{2}}

  31: {{5}}

  32: {{},{},{},{},{}}

  34: {{},{4}}

  41: {{6}}

  44: {{},{},{3}}

  47: {{2,3}}

  55: {{2},{3}}

  59: {{7}}

  62: {{},{5}}

  64: {{},{},{},{},{},{}}

MATHEMATICA

primeMS[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];

Select[Range[100], And@@Table[!Divisible[#, i], {i, Union@@primeMS/@primeMS[#]}]&]

CROSSREFS

Cf. A001222, A003963, A112798, A120383, A302242, A304360, A324846, A324847, A324848, A324849, A324850, A324927, A324928, A324930.

Sequence in context: A222044 A288937 A327063 * A175106 A216566 A205728

Adjacent sequences:  A324923 A324924 A324925 * A324927 A324928 A324929

KEYWORD

nonn

AUTHOR

Gus Wiseman, Mar 21 2019

STATUS

approved

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Last modified April 6 07:02 EDT 2020. Contains 333267 sequences. (Running on oeis4.)