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Search: id:A152007
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| A152007 |
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Numbers of the form (2^EulerPhi[3^n]-1)/3^n. |
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+0
2
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| 1, 1, 7, 9709, 222399981598543, 24057640120673299065081231814259802792690247621
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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The next term is too large to display.
With the exception of 7 there are no primes in this sequence.
All numbers in this sequence are squarefree.
a(n) is divisible by a(k) for every k < n.
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MATHEMATICA
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Table[(2^EulerPhi[3^n] - 1)/3^n, {n, 0, 10}]
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CROSSREFS
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Cf. A008776, A152008.
Sequence in context: A116631 A074489 A067248 this_sequence A131676 A134645 A115997
Adjacent sequences: A152004 A152005 A152006 this_sequence A152008 A152009 A152010
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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 19 2008
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EXTENSIONS
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Edited by N. J. A. Sloane (njas(AT)research.att.com), Nov 28 2008
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