%I A117543
%S A117543 1,4,0,7,6,0,4,3,4,3,4,9,0,2,3,3,8,8,2,2,2,7,5,0,9,2,5,4,1,3,8,7,7,2,5,
%T A117543 3,7,7,4,9,1,9,2,7,6,0,0,4,8,8,0,2,6,3,9,2,4,1,4,8,9,7,6,8,0,7,8,9,3,8,
%U A117543 0,2,8,0,9,7,6,0,3,5,3,8,6,9,6,3,5,0,4,4,3,4,8,6,1,3,1,3,8,2,5,7
%N A117543 Decimal expansion of the sum of the reciprocals of squared semiprimes.
%C A117543 Geoffrey Landis and Jonathan Vos Post (personal communication) show that 
               this constant equals ((P2)^2 + P4)/2, where P2 and P4 are constants 
               in A085548 and A085964, respectively.
%H A117543 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               PrimeZetaFunction.html">Math World: Prime Zeta Function</a>
%H A117543 Richard J. Mathar, <a href="http://arxiv.org/abs/0803.0900">Series of 
               Reciprocal Powers of k-almost Primes</a> [From T. D. Noe (noe(AT)sspectra.com), 
               Oct 09 2008]
%e A117543 0.14076043434902338822275...
%Y A117543 Cf. A001358 (semiprimes).
%Y A117543 A131653 [From T. D. Noe (noe(AT)sspectra.com), Oct 09 2008]
%Y A117543 Sequence in context: A057641 A133930 A077892 this_sequence A070433 A013666 
               A016682
%Y A117543 Adjacent sequences: A117540 A117541 A117542 this_sequence A117544 A117545 
               A117546
%K A117543 cons,nonn
%O A117543 0,2
%A A117543 T. D. Noe (noe(AT)sspectra.com), Mar 28 2006