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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A136364 a(n) = Sum_{ composite k, 1 <= k <= 10^n} (Number of divisors d of k with 1 < d < k). 1
8, 283, 5070, 73669, 966751, 11970035, 142725365, 1657511569, 18877697635, 211802823221, 2348286736298, 25785452449087, 280880375389758, 3039062263181055, 32693207724724247, 349957928177109417 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..16.

FORMULA

a(n) = A057494(n) - 2*10^n + 1 [From Max Alekseyev, May 10 2009]

EXAMPLE

a(1)=8 because there are 8 distinct divisors of composite numbers k through 10^1; these are for 4(1); 6(2); 8(2); 9(1); 10(2); and 1+2+2+1+2=8.

CROSSREFS

Cf. A136363.

Sequence in context: A226346 A217488 A247484 * A089670 A221612 A060355

Adjacent sequences:  A136361 A136362 A136363 * A136365 A136366 A136367

KEYWORD

easy,nonn

AUTHOR

Enoch Haga, Dec 26 2007, Dec 29 2007

EXTENSIONS

Edited by N. J. A. Sloane, Jan 12 2008

Three more terms from Max Alekseyev, May 10 2009

a(10) onward from Max Alekseyev, Jan 25 2010

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 23 03:08 EST 2019. Contains 319370 sequences. (Running on oeis4.)