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Search: id:A119989
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| A119989 |
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a(1)=1. a(n) = number of terms among the first (n-1) terms of the sequence which are coprime to n(n+1)/2. |
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+0
2
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| 1, 1, 2, 2, 4, 5, 3, 3, 5, 7, 5, 6, 11, 6, 4, 9, 11, 12, 8, 4, 11, 18, 9, 6, 21, 15, 8, 13, 14, 15, 17, 8, 16, 24, 7, 12, 36, 21, 8, 15, 20, 21, 19, 7, 22, 45, 14, 11, 32, 25, 14, 26, 33, 23, 10, 13, 35, 57, 14, 14, 60, 30, 15, 21, 24, 34, 33, 17, 25, 42, 21, 21, 72, 34, 14, 21, 26, 41
(list; graph; listen)
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OFFSET
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1,3
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PROGRAM
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(PARI) {m=79; print1(a=1, ", "); v=[a]; for(n=2, m, a=0; q=n*(n+1)/2; for(j=1, n-1, if(gcd(v[j], q)==1, a++)); print1(a, ", "); v=concat(v, a))} - (Klaus Brockhaus, Aug 15 2006)
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CROSSREFS
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Cf. A123953.
Sequence in context: A073018 A109295 A057899 this_sequence A137605 A130265 A129303
Adjacent sequences: A119986 A119987 A119988 this_sequence A119990 A119991 A119992
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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), Aug 03 2006
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EXTENSIONS
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More terms from Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Aug 15 2006
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