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

 

Logo

Invitation: celebrating 50 years of OEIS, 250000 sequences, and Sloane's 75th, there will be a conference at DIMACS, Rutgers, Oct 9-10 2014.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A057773 Sum_{i=1..n} nu_2 ( p(i) - 1), where p(i) is the i-th prime and nu_2(m) = exponent of highest power of 2 dividing m. 1
0, 1, 3, 4, 5, 7, 11, 12, 13, 15, 16, 18, 21, 22, 23, 25, 26, 28, 29, 30, 33, 34, 35, 38, 43, 45, 46, 47, 49, 53, 54, 55, 58, 59, 61, 62, 64, 65, 66, 68, 69, 71, 72, 78, 80, 81, 82, 83, 84, 86, 89, 90, 94, 95, 103, 104, 106, 107, 109, 112, 113, 115, 116, 117, 120, 122, 123 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Exponent of highest power of 2 dividing Euler Phi of primorials.

LINKS

Table of n, a(n) for n=0..66.

FORMULA

a(n)=A007814[A000010[A002110(n)]]

EXAMPLE

n=6, 6th primorial is 30030, Phi(30030)=5760=128.9.5, so a(6)=7, exponent of 128.

CROSSREFS

Cf. A007814, A000010, A002110.

Sequence in context: A022440 A088130 A046840 * A020486 A091428 A047499

Adjacent sequences:  A057770 A057771 A057772 * A057774 A057775 A057776

KEYWORD

nonn

AUTHOR

Labos Elemer, Nov 02 2000

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 August 29 06:14 EDT 2014. Contains 246187 sequences.