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A139024
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Number of distinct prime factors of n! + 2^n - 1.
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6
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1, 1, 1, 2, 1, 2, 1, 3, 2, 4, 1, 4, 4, 4, 4, 4, 2, 5, 2, 7, 3, 3, 3, 6, 3, 3, 5, 6, 5, 6, 3, 7, 5, 6, 3, 8, 5, 8, 4, 7, 7, 5, 9, 6, 5, 5, 4, 10, 5, 6, 3, 6, 4, 6, 6, 11, 5, 2, 4, 13, 2, 6, 4, 8, 5, 6, 4, 5, 7, 9, 2, 11, 7, 5, 8
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,4
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REFERENCES
| F. Luca and I. E. Shparlinsky, 2005. On the largest prime factor of n! + 2n - 1. J. Th. des Nombres de Bordeaux Vol.17, Fasc. 3
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MATHEMATICA
| a = {}; Do[AppendTo[a, n! + 2^n - 1], {n, 1, 40}]; b = {}; Do[c = Length[FactorInteger[a[[n]]]]; AppendTo[b, c], {n, 1, Length[a]}]; b
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CROSSREFS
| Cf. A127986, A127987, A139023.
Cf. A168177. [From Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Nov 19 2009]
Sequence in context: A194835 A054065 A194868 * A154958 A025806 A025802
Adjacent sequences: A139021 A139022 A139023 * A139025 A139026 A139027
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KEYWORD
| nonn
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AUTHOR
| Artur Jasinski (grafix(AT)csl.pl), Apr 06 2008, corrected Apr 22 2008
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EXTENSIONS
| a(1) - a(40) verified and a(41)- a(75) added by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Nov 19 2009
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