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

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A074370 Sum of the divisors of Sum_{i=1..n} prime(i). 1
3, 6, 18, 18, 56, 42, 90, 96, 217, 176, 378, 198, 432, 282, 630, 512, 1080, 672, 1080, 936, 1350, 912, 1440, 1404, 2268, 1760, 2480, 1832, 3420, 2400, 3960, 2472, 4032, 2840, 3990, 3240, 5400, 2856, 4608, 5200 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..40.

FORMULA

a(n) = A000203(A007504(n)). - R. J. Mathar, Apr 03 2011

EXAMPLE

sigma(prime(1) + prime(2) + prime(3)) = sigma(10) = 18, so a(3) = 18.

MAPLE

A007504 := proc(n) add( ithprime(i), i=1..n) ; end proc:

A074370 := proc(n) numtheory[sigma](A007504(n)) ; end proc: # R. J. Mathar, Apr 03 2011

MATHEMATICA

s = 0; l = {}; Do[s = s + Prime[i]; l = Append[l, DivisorSigma[1, s]], {i, 1, 100}]; l

DivisorSigma[1, #]&/@Accumulate[Prime[Range[50]]]  (* Harvey P. Dale, Mar 13 2011 *)

CROSSREFS

Sequence in context: A248324 A078318 A193433 * A174101 A088339 A064400

Adjacent sequences:  A074367 A074368 A074369 * A074371 A074372 A074373

KEYWORD

easy,nonn

AUTHOR

Joseph L. Pe, Sep 24 2002

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 December 13 17:37 EST 2019. Contains 329970 sequences. (Running on oeis4.)