login
A134228
Sum of the odd primes <= 2*10^n.
2
75, 4225, 277048, 21171189, 1709600811, 142913828920, 12272577818050, 1075207199997332, 95673602693282038, 8617752113620426557, 783964147695858014234, 71904055278788602481892, 6640510710493148698166594, 616876923984020487671442310
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
Sequence in context: A017738 A166725 A075913 * A324452 A110902 A207546
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