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Search: id:A108510
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| 1979, 2699, 7649, 1131569, 2482199, 2886839, 90425537, 2774476799
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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There is no further term up to prime(300000000).
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EXAMPLE
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Let n be a natural number and m=3^n*7*90425537;
then sigma(phi(m)) = sigma(3^(n-1)*2*6*90425536) = sigma(3^n*2^8*677*2087) = sigma(3^n)*8*90425538 = sigma(3^n)*sigma(7)*sigma(90425537) = sigma(3^n*7*90425537) = sigma(m),
hence m is in A033631 and the prime number 90425537 is a term of this sequence.
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CROSSREFS
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Cf. A000027, A033631.
Adjacent sequences: A108507 A108508 A108509 this_sequence A108511 A108512 A108513
Sequence in context: A135845 A121995 A061998 this_sequence A125490 A035870 A028238
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KEYWORD
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more,nonn
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AUTHOR
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Farideh Firoozbakht (f.firoozbakht(AT)math.ui.ac.ir), Jun 07 2005
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