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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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0
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OFFSET
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1,1
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COMMENTS
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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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LINKS
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Table of n, a(n) for n=1..3.
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PROG
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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.
Sequence in context: A223452 A015223 A129625 * A199901 A251249 A264673
Adjacent sequences: A133379 A133380 A133381 * A133383 A133384 A133385
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KEYWORD
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nonn,bref
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AUTHOR
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M. F. Hasler, Oct 28 2007
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STATUS
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approved
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