cp's OEIS Frontend

A119433 Primitive elements of A119432.

%I A119433 #14 Nov 07 2020 11:36:42
%S A119433 2,105,165,195,3003,3927,4389,4641,4845,5187,5313,5865,6555,7395,7905,
%T A119433 8265,8835,9435,10005,10455,10545,10695,10965,11685,11985,12255,12765,
%U A119433 13395,13485,13515,14145,14835,15045,15105,15555,16215,16815,17085
%N A119433 Primitive elements of A119432.
%C A119433 Elements of A119432 that are not divisible by any smaller element of that sequence.
%C A119433 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
%H A119433 Charles R Greathouse IV, <a href="/A119433/b119433.txt">Table of n, a(n) for n = 1..10000</a>
%F A119433 2 followed by odd elements of A119431.
%e A119433 From _Peter Munn_, Oct 23 2020: (Start)
%e A119433 Initial terms, showing factorization:
%e A119433    n   a(n)
%e A119433    1      2 = 2
%e A119433    2    105 = 3 * 5 * 7
%e A119433    3    165 = 3 * 5 * 11
%e A119433    4    195 = 3 * 5 * 13
%e A119433    5   3003 = 3 * 7 * 11 * 13
%e A119433    6   3927 = 3 * 7 * 11 * 17
%e A119433    7   4389 = 3 * 7 * 11 * 19
%e A119433    8   4641 = 3 * 7 * 13 * 17
%e A119433    9   4845 = 3 * 5 * 17 * 19
%e A119433   10   5187 = 3 * 7 * 13 * 19
%e A119433   11   5313 = 3 * 7 * 11 * 23
%e A119433   12   5865 = 3 * 5 * 17 * 23
%e A119433   13   6555 = 3 * 5 * 19 * 23
%e A119433   14   7395 = 3 * 5 * 17 * 29
%e A119433   15   7905 = 3 * 5 * 17 * 31
%e A119433 (End)
%t A119433 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 *)
%Y A119433 Subsequence of A005117, A119432.
%Y A119433 Cf. A103288.
%K A119433 nonn
%O A119433 1,1
%A A119433 _Franklin T. Adams-Watters_, May 19 2006