A119433 Primitive elements of A119432.

2, 105, 165, 195, 3003, 3927, 4389, 4641, 4845, 5187, 5313, 5865, 6555, 7395, 7905, 8265, 8835, 9435, 10005, 10455, 10545, 10695, 10965, 11685, 11985, 12255, 12765, 13395, 13485, 13515, 14145, 14835, 15045, 15105, 15555, 16215, 16815, 17085

Offset: 1

Author

Franklin T. Adams-Watters, May 19 2006

Keywords

• nonn

Comments

Elements of A119432 that are not divisible by any smaller element of that sequence.

Appears to be the lexicographically latest sequence of squarefree numbers such that all numbers with abundance >= -1 (see A103288) are divisible by one of the terms. - Peter Munn, Oct 19 2020

Examples

			From _Peter Munn_, Oct 23 2020: (Start)
Initial terms, showing factorization:
   n   a(n)
   1      2 = 2
   2    105 = 3 * 5 * 7
   3    165 = 3 * 5 * 11
   4    195 = 3 * 5 * 13
   5   3003 = 3 * 7 * 11 * 13
   6   3927 = 3 * 7 * 11 * 17
   7   4389 = 3 * 7 * 11 * 19
   8   4641 = 3 * 7 * 13 * 17
   9   4845 = 3 * 5 * 17 * 19
  10   5187 = 3 * 7 * 13 * 19
  11   5313 = 3 * 7 * 11 * 23
  12   5865 = 3 * 5 * 17 * 23
  13   6555 = 3 * 5 * 19 * 23
  14   7395 = 3 * 5 * 17 * 29
  15   7905 = 3 * 5 * 17 * 31
(End)
		

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Crossrefs

Subsequence of A005117, A119432.

Cf. A103288.

Programs

Mathematica

Block[{a = {}}, Do[If[And[NoneTrue[a, Mod[i, #] == 0 &], 2 EulerPhi[i] <= i], AppendTo[a, i]], {i, 20000}]; a] (* Michael De Vlieger, Nov 05 2020 *)

Formula

2 followed by odd elements of A119431.