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Search: id:A147580
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| A147580 |
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Numbers with exactly 7 distinct odd prime divisors {3,5,7,11,13,17,19} |
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+0
13
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| 4849845, 14549535, 24249225, 33948915, 43648605, 53348295, 63047985, 72747675, 82447365, 92147055, 101846745, 121246125, 130945815, 160044885, 169744575, 189143955, 218243025, 237642405, 247342095, 266741475, 276441165, 305540235
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OFFSET
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1,1
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COMMENT
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Successive numbers k such that EulerPhi[x]/x = m
( Family of sequences for successive n odd primes )
m=2/3 numbers with exactly 1 distinct prime divisor {3} see A000244
m=8/15 numbers with exactly 2 distinct prime divisors {3,5} see A033849
m=16/35 numbers with exactly 3 distinct prime divisors {3,5,7} see A147576
m=32/77 numbers with exactly 4 distinct prime divisors {3,5,7,11} see A147577
m=384/1001 numbers with exactly 5 distinct prime divisors {3,5,7,11,13} see A147578
m=6144/17017 numbers with exactly 6 distinct prime divisors {3,5,7,11,13,17} see A147579
m=3072/323323 numbers with exactly 7 distinct prime divisors {3,5,7,11,13,17,19} see A147580
m=110592/323323 numbers with exactly 8 distinct prime divisors {3,5,7,11,13,17,19,23} see A147581
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MATHEMATICA
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a = {}; Do[If[EulerPhi[4849845 x] == 1658880 x, AppendTo[a, 4849845 x]], {x, 1, 100}]; a (*Artur Jasinski*)
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CROSSREFS
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A060735, A143207, A147571-A147575, A147576-A147580
Sequence in context: A017538 A034637 A043637 this_sequence A043662 A125834 A089234
Adjacent sequences: A147577 A147578 A147579 this_sequence A147581 A147582 A147583
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KEYWORD
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nonn
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AUTHOR
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Artur Jasinski (grafix(AT)csl.pl), Nov 07 2008
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