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A136177 Number of exponents in the prime factorization of n that are coprime to n. 2
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; text; internal format)
OFFSET
1,6
LINKS
EXAMPLE
8000 = 2^6 * 5^3. 6 is not coprime to 8000, but 3 is. So a(8000) = 1.
MATHEMATICA
Table[Length[Select[Table[FactorInteger[n][[i, 2]], {i, 1, Length[FactorInteger[n]]}], GCD[ #, n] == 1 &]], {n, 2, 90}] (* Stefan Steinerberger, Dec 21 2007 *)
Join[{0}, Table[Count[FactorInteger[n][[All, 2]], _?(CoprimeQ[#, n]&)], {n, 2, 110}]] (* Harvey P. Dale, Aug 05 2018 *)
PROG
(PARI) A136177(n)={local(t); sum(j=1, #t=factor(n)[, 2]~, gcd(n, t[j])==1)} \\ M. F. Hasler, Dec 21 2007
CROSSREFS
Cf. A136176.
Sequence in context: A086257 A161098 A354999 * A212178 A322818 A362611
KEYWORD
nonn,easy
AUTHOR
Leroy Quet, Dec 19 2007
EXTENSIONS
More terms from M. F. Hasler and Stefan Steinerberger, Dec 21 2007
STATUS
approved

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Last modified March 29 00:26 EDT 2024. Contains 371264 sequences. (Running on oeis4.)