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A136363 a(n) = Sum_{ composite k, 1 <= k <= 10^n} (Sum of divisors d of k with 1 < d < k). +0
2
23, 3150, 321582, 32241015, 3224590836, 322466618438, 32246696794797, 3224670272194238, 322467032612360629, 32246703337400266401, 3224670334173560419030, 322467033423857340138979 (list; graph; listen)
OFFSET

1,1

FORMULA

a(n) = A072692(n) - 10^n*(10^n+3)/2 + 1 [From Max Alekseyev (maxale(AT)gmail.com), May 10 2009]

EXAMPLE

a(1)=23 because the divisors through 10^1 are as follows: 4 (2); 6 (2,3); 8 (2,4); 9 (3); 10 (2,5). The sum is 2+2+3+2+4+3+2+5=23.

CROSSREFS

Cf. A136364.

Sequence in context: A088385 A030461 A152521 this_sequence A134798 A103443 A059000

Adjacent sequences: A136360 A136361 A136362 this_sequence A136364 A136365 A136366

KEYWORD

easy,more,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

Extended by Max Alekseyev (maxale(AT)gmail.com), May 10 2009

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Last modified November 25 08:46 EST 2009. Contains 167481 sequences.


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