OFFSET
1,1
FORMULA
Beginning with 3, compute 10^n sums of odds, less odd composites, for each 10^n.
a(n) = sum(p: p in A000040, 2<p <=2*10^n). a(n) = A007504(k)-2, where k=A049084[A007917(2*10^n)]. - R. J. Mathar, Oct 28 2007
EXAMPLE
a(1)=75 because that is the sum of odds (3+5+7+11+13+17+19=75) less composites (9,15,21) under 10^1 (beginning with 3).
PROG
(PARI) a(n) = sum(i=3, 2*10^n, i*isprime(i)); \\ Michel Marcus, Jun 08 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Enoch Haga, Oct 14 2007
EXTENSIONS
Better definition from R. J. Mathar, Oct 28 2007
a(9)-a(14) from Hiroaki Yamanouchi, Jul 06 2014
STATUS
approved