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 A116537 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. 1
 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; refs; listen; history; text; internal format)
 OFFSET 1,5 LINKS EXAMPLE 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. PROG (Perl) #!/usr/bin/perl -w 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 "; } # from Hugo van der Sanden, Mar 30 2006 CROSSREFS Cf. A096216. Sequence in context: A135822 A242111 A209919 * A194307 A048225 A155481 Adjacent sequences:  A116534 A116535 A116536 * A116538 A116539 A116540 KEYWORD nonn AUTHOR Leroy Quet, Mar 27 2006 EXTENSIONS More terms from Hugo van der Sanden, Mar 31 2006 STATUS approved

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Last modified October 22 22:34 EDT 2019. Contains 328335 sequences. (Running on oeis4.)