OFFSET
1,1
COMMENTS
The old entry with this sequence number was a duplicate of A081532.
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..10000
R. K. Guy, Conway's prime producing machine, Math. Mag. 56 (1983), no. 1, 26-33 (see p. 33).
MATHEMATICA
(Rest@ FoldList[ Plus, 0, DivisorSigma[0, Range@ Prime@ 100]])[[ Prime@ Range@ 100]] -1 (* Giovanni Resta, Jun 09 2015 *)
PROG
(Python)
from math import isqrt
from sympy import prime
def A085683(n): return -(s:=isqrt(m:=prime(n)))**2+(sum(m//k for k in range(1, s+1))<<1)-1 # Chai Wah Wu, Oct 23 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Oct 28 2008
STATUS
approved