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

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

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 December 19 18:23 EST 2014. Contains 252239 sequences.