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A139023 Smallest prime factor of n! + 2^n - 1. +0
6
2, 5, 13, 3, 151, 3, 5167, 3, 7, 3, 39918847, 3, 17, 3, 7, 3, 829, 3, 25561, 3, 7, 3, 929, 3, 67, 3, 7, 3, 37, 3, 941, 3, 7, 3, 31, 3, 47, 3, 7, 3 (list; graph; listen)
OFFSET

1,1

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

MATHEMATICA

a = {}; Do[AppendTo[a, n! + 2^n - 1], {n, 1, 40}]; b = {}; Do[c = FactorInteger[a[[n]]]; d = c[[1]]; AppendTo[b, d[[1]]], {n, 1, Length[a]}]; b

CROSSREFS

Cf. A127986, A127987, A139024.

Adjacent sequences: A139020 A139021 A139022 this_sequence A139024 A139025 A139026

Sequence in context: A135331 A135329 A114508 this_sequence A067365 A112838 A111296

KEYWORD

nonn

AUTHOR

Artur Jasinski (grafix(AT)csl.pl), Apr 06 2008, corrected Apr 22 2008

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Last modified October 11 13:47 EDT 2008. Contains 144830 sequences.


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