A168473 - OEIS

%I #10 Mar 21 2019 04:36:51

%S 181,293,907,2311,2971,3547,4019,4523,5651,7103,7753,8419,14489,15443,

%T 17417,18097,18443,22171,31123,32063,41611,42683,44851,48761,67829,

%U 69221,79273,98047,103903,107347,114407,122597,132967,149909,154081

%N Primes in A168472.

%H Robert Israel, <a href="/A168473/b168473.txt">Table of n, a(n) for n = 1..10000</a>

%p N:= 10^4: # to get all a(n) where A006881(n) < N

%p Primes:= select(isprime, [2, seq(2*k+1, k=1..floor(N/2))]):

%p L:= sort(convert({seq(seq(p*q, q=Primes[1..ListTools:-BinaryPlace(Primes, N/p)]), p=Primes)} minus {seq(p^2, p=Primes)}, list)):

%p A168472:= ListTools:-PartialSums(L):

%p select(isprime, A168472); # _Robert Israel_, Mar 20 2019

%t f[n_]:=Last/@FactorInteger[n]=={1,1}; s=0;lst={};Do[If[f[n],If[PrimeQ[s+=n],AppendTo[lst,s]]],{n,7!}];lst

%t With[{nn=50},Select[Accumulate[Union[Times@@@Subsets[Prime[Range[2nn]],{2}]]],PrimeQ,nn]] (* _Harvey P. Dale_, Aug 08 2013 *)

%Y Cf. A168472.

%K nonn

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, Nov 26 2009