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Search: id:A133382
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| A133382 |
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Numbers n such that gcd( n!-1, 2^n-1 ) is neither 1 nor 2n+1. |
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1
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OFFSET
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1,1
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COMMENT
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This subsequence of A068483 lists the rare exceptions for which gcd( N!, 2^N-1 ) <> 2N+1. Is it finite? Are all elements multiples of 5?
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PROGRAM
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(PARI) for(n=1, 10^5, if((g=gcd(n!-1, 2^n-1)-1) & g!=2*n, print(n", ")))
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CROSSREFS
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Cf. A068483, A068480.
Adjacent sequences: A133379 A133380 A133381 this_sequence A133383 A133384 A133385
Sequence in context: A055561 A015223 A129625 this_sequence A017791 A017738 A166725
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KEYWORD
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nonn,bref
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AUTHOR
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M. F. Hasler (Maximilian.Hasler(AT)gmail.com), Oct 28 2007
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