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Numbers k such that 1 < gcd(k, 70) < k and A007947(k) does not divide 70.
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%I #13 Dec 02 2023 09:13:45

%S 6,12,15,18,21,22,24,26,30,34,36,38,42,44,45,46,48,52,54,55,58,60,62,

%T 63,65,66,68,72,74,75,76,77,78,82,84,85,86,88,90,91,92,94,95,96,102,

%U 104,105,106,108,110,114,115,116,118,119,120,122,124,126,130,132,133,134,135,136,138,142,144,145,146

%N Numbers k such that 1 < gcd(k, 70) < k and A007947(k) does not divide 70.

%C The asymptotic density of this sequence is 23/35. - _Amiram Eldar_, Dec 02 2023

%H Michael De Vlieger, <a href="/A362011/b362011.txt">Table of n, a(n) for n = 1..10000</a>

%H Michael De Vlieger, <a href="/A362011/a362011.png">Diagram showing numbers k in this sequence</a> instead as k mod 70 arranged in rows, labeled and in large black circles, else gray dots if coprime to 70, purple if k = 1, red if k | 70, and gold if rad(k) | 70.

%F This sequence is { N \ { A108513 U A235583 } }.

%t With[{n = 70}, Select[Range[200], And[! CoprimeQ[#, n], ! Divisible[n, Times @@ FactorInteger[#][[All, 1]]]] & ] ]

%Y Cf. A007947, A108513, A235583.

%K nonn

%O 1,1

%A _Michael De Vlieger_, Apr 04 2023