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Search: id:A078334
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| A078334 |
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Primes in A005728, which counts the terms in the Farey sequence of order n. |
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+0
2
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| 2, 3, 5, 7, 11, 13, 19, 23, 29, 43, 47, 59, 73, 97, 103, 151, 173, 181, 271, 397, 433, 491, 883, 941, 1087, 1103, 1163, 1193, 1229, 1427, 1471, 1697, 2143, 2273, 2657, 2903, 3533, 3677, 4073, 4129, 4201, 4259, 4637, 5023, 5107, 5953, 6163, 6599, 7177, 7237
(list; graph; listen)
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OFFSET
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0,1
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REFERENCES
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H. Rademacher, Lectures on Elementary Number Theory, 1964. pp. 5-11.
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LINKS
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Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
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EXAMPLE
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The Farey sequence of order 6 is {0, 1/6, 1/5, 1/4, 1/3, 2/5, 1/2, 3/5, 2/3, 3/4, 4/5, 5/6, 1}, which has 13 terms, so 13 is in the sequence.
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MATHEMATICA
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fc[n_] := 1+Sum[EulerPhi[k], {k, 1, n}]; Select[fc/@Range[200], PrimeQ]
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CROSSREFS
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Sequence in context: A050437 A096246 A106639 this_sequence A108696 A092581 A130807
Adjacent sequences: A078331 A078332 A078333 this_sequence A078335 A078336 A078337
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KEYWORD
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easy,nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), Nov 21 2002
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