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A064130
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Number of divisors of 2^n + 1 that are relatively prime to 2^m + 1 for all 0 < m < n.
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1
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2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 4, 2, 2, 2, 4, 2, 2, 2, 4, 2, 4, 4, 8, 2, 2, 4, 4, 2, 4, 4, 8, 4, 4, 4, 8, 2, 2, 4, 4, 2, 4, 2, 16, 4, 4, 2, 8, 8, 4, 4, 4, 4, 4, 4, 4, 8, 2, 2, 16, 2, 4, 8, 4, 4, 4, 4, 4, 4, 4, 4, 16, 2, 8, 8, 16, 2, 4, 8, 16, 32, 4, 2, 16, 2, 8, 8, 8, 8, 2, 4, 8, 4, 2, 16, 8, 4
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OFFSET
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0,1
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LINKS
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MATHEMATICA
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a = {1}; Do[ d = Divisors[ 2^n + 1 ]; l = Length[ d ]; c = 0; k = 1; While[ k < l + 1, If[ Union[ GCD[ a, d[ [ k ] ] ] ] == {1}, c++ ]; k++ ]; Print[ c ]; a = Union[ Flatten[ Append[ a, Transpose[ FactorInteger[ 2^n + 1 ] ][ [ 1 ] ] ] ] ], {n, 0, 100} ]
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PROG
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(PARI) { allocatemem(932245000); for (n=0, 250, d=divisors(2^n + 1); l=length(d); a=0; for (i=1, l, t=1; for (m=1, n - 1, p=2^m + 1; if (gcd(d[i], p)!=1, t=0; break)); if (t, a++)); write("b064130.txt", n, " ", a) ) } \\ Harry J. Smith, Sep 08 2009
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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Definition corrected from 12^m + 1 to 2^m + 1 by Harry J. Smith, Sep 08 2009
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STATUS
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approved
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