This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A152447 #6 Mar 30 2012 17:39:46
%S A152447 1,7,1,0,5,1,8,9,2,9,7,9,9,9,6,6,3,6,6,2,2,2,0,2,5,6,4,3,7,2,3,7,4,2,
%T A152447 1,3,9,9,1,2,4,6,6,1,2,0,3,5,5,0,0,5,9,7,4,9,1,0,7,9,9,7,0,7,0,0,4,6,
%U A152447 9,9,2,9,7,2,8,4,8,1,2,7
%N A152447 Decimal expansion of the sum_q 1/(q*(q-1)) over the semiprimes q = A001358.
%C A152447 The semiprime analog of A136141. To obtain the (smaller) sum over the squarefree semiprimes A006881, subtract the prime zeta functions of 4 ( A085964 ), 6, 8 etc. from this constant here. The first term in the representation as the geometric series in powers 1/q^s is in A117543 .
%H A152447 R. J. Mathar, <a href="http://arxiv.org/abs/0803.0900">Series of reciprocal powers of k-almost primes</a>, constant B_{2,1} in table 8.
%F A152447 Equals 0.17105189297999663662220256437237421399124661203550059749107997... = 1/(4*3)+1/(6*5)+1/(9*8)+1/(10*9)+...
%K A152447 cons,nonn
%O A152447 0,2
%A A152447 _R. J. Mathar_, Dec 04 2008