|
| |
|
|
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; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
FORMULA
| a(n) = A057494(n) - 2*10^n + 1 [From Max Alekseyev (maxale(AT)gmail.com), 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: A179570 A201188 A079929 * A089670 A060355 A060859
Adjacent sequences: A136361 A136362 A136363 * A136365 A136366 A136367
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Enoch Haga (Enokh(AT)comcast.net), Dec 26 2007, Dec 29 2007
|
|
|
EXTENSIONS
| Edited by N. J. A. Sloane (njas(AT)research.att.com), Jan 12 2008
Three more terms from Max Alekseyev (maxale(AT)gmail.com), May 10 2009
a(10) onward from Max Alekseyev (maxale(AT)gmail.com), Jan 25 2010
|
| |
|
|
