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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A296358 Denominator of the sum of the reciprocals of the first n composite numbers. 10
4, 12, 24, 72, 360, 360, 2520, 504, 1008, 336, 1680, 1680, 18480, 18480, 92400, 1201200, 10810800, 10810800, 10810800, 21621600, 21621600, 367567200, 52509600, 52509600, 997682400, 997682400, 997682400, 6983776800, 6983776800, 6983776800 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Same as A282512 without the initial 1.

LINKS

Table of n, a(n) for n=1..30.

FORMULA

Gerry Felderman (Personal communication, Dec 15 2017) observes that Sum_{k=1..n} 1/composite(k) (= A250133(n)/A296358(n)) ~ log(n) - loglog(n) ~ log pi(n) as n -> oo.

EXAMPLE

1/4, 5/12, 13/24, 47/72, 271/360, 301/360, 2287/2520, 491/504, 1045/1008, 367/336, 1919/1680, 1999/1680, 22829/18480, ... = A250133/A296358

CROSSREFS

Numerators are in A250133.

The following fractions are all related to each other: Sum 1/n: A001008/A002805, Sum 1/prime(n): A024451/A002110 and A106830/A034386, Sum 1/nonprime(n): A282511/A282512, Sum 1/composite(n): A250133/A296358.

Sequence in context: A051193 A216244 A215223 * A282512 A025543 A064354

Adjacent sequences:  A296355 A296356 A296357 * A296359 A296360 A296361

KEYWORD

nonn,frac

AUTHOR

N. J. A. Sloane, Dec 15 2017

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy .

Last modified February 22 19:27 EST 2018. Contains 299469 sequences. (Running on oeis4.)