A250039 - OEIS

%I #23 Jan 29 2015 09:17:59

%S 2,3,4,5,6,7,8,9,10,11,12,13,14,15,32,34,36,38,40,42,44,46,48,51,54,

%T 57,60,63,64,66,68,70,72,74,76,78,80,85,90,95,96,98,99,100,102,104,

%U 105,106,108,110,111,112,119,126,128,130,132,134,136,138,140,142

%N Numbers n such that m = floor(n/16) 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=16. In particular, they define the property RTNC(b).

%C This list is an infinite subset of A248502 with which it shares the first 111 entries.

%H Stanislav Sykora, <a href="/A250039/b250039.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=16) = {while (((m=gcd(n\b, n)) != 1), if (m == 0, return (1)); n = n\b; ); return (0); } \\ _Michel Marcus_, Jan 29 2015

%Y Cf. A248502, A250038, A250041.

%Y Other lists of right-truncatable numbers with the property RTNC(b): A005823 (b=3), A250037 (b=4), A250041 (b=10), A250043 (b=9), A250045 (b=8), A250047 (b=7), A250049 (b=6), A250051 (b=5).

%K nonn,base

%O 1,1

%A _Stanislav Sykora_, Dec 07 2014