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Search: id:A116537
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| A116537 |
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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. |
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+0
2
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| 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, 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, 21, 15, 33, 9, 34, 15, 21, 17, 27, 12, 39, 17, 28, 13, 41, 14, 42, 19, 24, 20, 36, 15, 45
(list; graph; listen)
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OFFSET
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1,5
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EXAMPLE
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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.
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PROGRAM
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(PERL) #!/usr/bin/perl -w # from Hugo van der Sanden, hv(AT)crypt.org, Mar 30 2006
use Math::Pari qw/ gcd eulerphi /;
$| = 1;
$n = 2;
%seen = (1 => 1);
while (1) {
$v = eulerphi($n) - grep gcd($n, $_) == 1, keys %seen;
$seen{$v} = 1;
++$n;
print "$v ";
}
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CROSSREFS
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Cf. A096216.
Sequence in context: A135821 A134545 A135822 this_sequence A048225 A075148 A066728
Adjacent sequences: A116534 A116535 A116536 this_sequence A116538 A116539 A116540
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet (qq-quet(AT)mindspring.com), Mar 27 2006
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EXTENSIONS
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More terms from Hugo van der Sanden, Mar 31 2006
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