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Numbers n such that m = floor(n/7) is not coprime to n and, if nonzero, m is also a term of the sequence.
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%I #14 Jan 29 2015 09:18:40

%S 2,3,4,5,6,14,16,18,20,21,24,27,28,30,32,34,35,40,42,44,45,46,48,98,

%T 100,102,104,112,114,116,118,126,128,129,130,132,140,142,144,145,146,

%U 147,150,153,168,170,171,172,174,189,192,195,196,198,200,202,210

%N Numbers n such that m = floor(n/7) is not coprime to n and, if nonzero, m is also a term of the sequence.

%C See the comments in A250041 which all apply, except for the setting of the base, b=7. In particular, they define the property RTNC(b).

%H Stanislav Sykora, <a href="/A250047/b250047.txt">Table of n, a(n) for n = 1..10000</a>

%H Stanislav Sykora, <a href="https://oeis.org/wiki/File:GeneticThreads.txt">PARI/GP scripts for genetic threads</a>, with code and comments

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Coprime_integers">Coprime integers</a>

%o (PARI) See the link

%o (PARI) is_rtnc(n, b=7) = {while (((m=gcd(n\b, n)) != 1), if (m == 0, return (1)); n = n\b; ); return (0); } \\ _Michel Marcus_, Jan 22 2015

%Y Cf. A250041 (b=10), A250046.

%Y Other lists of right-truncatable numbers with the property RTNC(b):

%Y A005823 (b=3), A250037 (b=4), A250039 (b=16), A250043 (b=9), A250045 (b=8), A250049 (b=6), A250051 (b=5).

%K nonn,base

%O 1,1

%A _Stanislav Sykora_, Jan 15 2015