OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
FORMULA
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:
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
KEYWORD
easy,nonn
AUTHOR
Joseph L. Pe, Sep 24 2002
STATUS
approved