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Search: id:A039768
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| A039768 |
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GCD(phi(a(n)),a(n)-1) = number of divisors of (a(n)-1). |
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+0
1
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| 2, 3, 105, 133, 153, 185, 345, 377, 425, 585, 637, 665, 777, 805, 825, 873, 897, 905, 949, 1017, 1090, 1113, 1209, 1225, 1261, 1305, 1309, 1385, 1449, 1525, 1545, 1573, 1645, 1681, 1785, 1813, 1833, 1865, 1885, 1957, 1981, 2009, 2057, 2077, 2105
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OFFSET
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1,1
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EXAMPLE
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phi(105)=48, gcd(48,104)=8, 104 is divisible by {1,2,4,8,13,26,52,104}.
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CROSSREFS
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Cf. A000005, A000010.
Sequence in context: A128931 A062657 A041589 this_sequence A097653 A107108 A129729
Adjacent sequences: A039765 A039766 A039767 this_sequence A039769 A039770 A039771
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KEYWORD
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nonn,easy
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AUTHOR
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Olivier Gerard (ogerard(AT)ext.jussieu.fr)
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