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A227082 a(n) is the least positive integer not yet in the sequence coprime to a(d) for every proper divisor d of n. 2

%I

%S 1,2,3,5,4,7,6,9,8,11,10,13,12,17,19,23,14,25,15,21,29,27,16,31,33,35,

%T 37,41,18,43,20,47,49,39,53,59,22,61,55,67,24,65,26,71,73,45,28,79,77,

%U 83,85,89,30,97,51,91,32,95,34,101,36,57,103,107,109,113,38,121,115,125,40,127,42,63,119,131,133,137,44,139,143,145,46,149

%N a(n) is the least positive integer not yet in the sequence coprime to a(d) for every proper divisor d of n.

%C This is a permutation of the positive integers.

%C The subsequence (a(prime(i))) is strictly increasing.

%C a(i) < a(prime(j)) implies i < prime(j).

%H Paul Tek, <a href="/A227082/b227082.txt">Table of n, a(n) for n = 1..10000</a>

%H Paul Tek, <a href="/A227082/a227082.pl.txt">PERL program for this sequence</a>

%e a(1) = min { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, ... } = 1

%e a(2) = min { 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, ... } = 2

%e a(3) = min { 3, 4, 5, 6, 7, 8, 9, 10, 11, ... } = 3

%e a(4) = min { 5, 7, 9, 11, ... } = 5

%e a(5) = min { 4, 6, 7, 8, 9, 10, 11, ... } = 4

%e a(6) = min { 7, 11, ... } = 7

%o (Perl) See Tek link.

%Y Cf. A227142.

%K nonn

%O 1,2

%A _Paul Tek_, Jun 30 2013

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Last modified January 27 08:31 EST 2020. Contains 331293 sequences. (Running on oeis4.)