A134228 - OEIS

%I #16 Oct 17 2014 23:25:35

%S 75,4225,277048,21171189,1709600811,142913828920,12272577818050,

%T 1075207199997332,95673602693282038,8617752113620426557,

%U 783964147695858014234,71904055278788602481892,6640510710493148698166594,616876923984020487671442310

%N Sum of the odd primes <= 2*10^n.

%F Beginning with 3, compute 10^n sums of odds, less odd composites, for each 10^n.

%F 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

%e 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).

%o (PARI) a(n) = sum(i=3, 2*10^n, i*isprime(i)); \\ _Michel Marcus_, Jun 08 2014

%Y Cf. A134229, A134230.

%K nonn

%O 1,1

%A _Enoch Haga_, Oct 14 2007

%E Better definition from _R. J. Mathar_, Oct 28 2007

%E a(9)-a(14) from _Hiroaki Yamanouchi_, Jul 06 2014