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A136177
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Number of exponents in the prime-factorization of n that are coprime to n.
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2
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0, 1, 1, 0, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 2, 0, 1, 1, 1, 1, 2, 2, 1, 1, 1, 2, 0, 1, 1, 3, 1, 1, 2, 2, 2, 0, 1, 2, 2, 2, 1, 3, 1, 1, 2, 2, 1, 1, 1, 1, 2, 1, 1, 1, 2, 2, 2, 2, 1, 2, 1, 2, 2, 0, 2, 3, 1, 1, 2, 3, 1, 0, 1, 2, 2, 1, 2, 3, 1, 1, 1, 2, 1, 2, 2, 2, 2, 2, 1, 2, 2, 1, 2, 2, 2, 2, 1, 1, 2, 0, 1, 3, 1, 2, 3
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,6
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EXAMPLE
| 8000 = 2^6 * 5^3. 6 is not coprime to 8000, but 3 is. So a(8000) = 1.
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MATHEMATICA
| Table[Length[Select[Table[FactorInteger[n][[i, 2]], {i, 1, Length[FactorInteger[n]]}], GCD[ #, n] == 1 &]], {n, 2, 90}] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 21 2007
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PROG
| (PARI) A136177(n)={local(t); sum(j=1, #t=factor(n)[, 2]~, gcd(n, t[j])==1)} \\ - M. F. Hasler, Dec 21 2007
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CROSSREFS
| Cf. A136176.
Sequence in context: A076398 A086257 A161098 * A066922 A033183 A090677
Adjacent sequences: A136174 A136175 A136176 * A136178 A136179 A136180
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KEYWORD
| nonn,easy
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AUTHOR
| Leroy Quet, Dec 19 2007
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EXTENSIONS
| More terms from M. F. Hasler (Maximilian.Hasler(AT)gmail.com) and Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 21 2007
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