login
This site is supported by donations to The OEIS Foundation.

 

Logo

Many excellent designs for a new banner were submitted. We will use the best of them in rotation.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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

Table of n, a(n) for n=1..105.

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

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: A076398 A086257 A161098 * A212178 A066922 A033183

Adjacent sequences:  A136174 A136175 A136176 * A136178 A136179 A136180

KEYWORD

nonn,easy

AUTHOR

Leroy Quet, Dec 19 2007

EXTENSIONS

More terms from M. F. Hasler and Stefan Steinerberger, Dec 21 2007

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified April 21 11:47 EDT 2014. Contains 240824 sequences.