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%I #14 Jul 19 2016 11:06:47
%S 1,0,1,1,3,1,4,2,3,2,6,3,7,4,4,5,9,3,10,4,7,5,13,4,12,7,11,6,16,4,17,
%T 8,10,9,12,6,21,9,14,8,23,6,24,11,13,13,27,9,25,10,19,12,30,9,22,13,
%U 21,15,33,9,34,15,21,17,27,12,39,17,28,13,41,14,42,19,24,20,36,15,45
%N a(1)=1. a(n) = number of positive integers that are < n, are coprime to n and do not occur among the first n-1 terms of the sequence.
%e The positive integers which are both less than 9 and are coprime to 9 are 1, 2, 4, 5, 7 and 8. Of these, only the three integers 5, 7 and 8 do not occur earlier in the sequence, so a(9)=3.
%o (Perl) #!/usr/bin/perl -w
%o use Math::PARI qw/ gcd eulerphi /;
%o $| = 1;
%o $n = 2;
%o %seen = (1 => 1);
%o while (1) {
%o $v = eulerphi($n) - grep gcd($n, $_) == 1, keys %seen;
%o $seen{$v} = 1;
%o ++$n;
%o print "$v ";
%o } # from _Hugo van der Sanden_, Mar 30 2006
%Y Cf. A096216.
%K nonn
%O 1,5
%A _Leroy Quet_, Mar 27 2006
%E More terms from _Hugo van der Sanden_, Mar 31 2006
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