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%I #27 Oct 28 2021 13:06:09
%S 8,7,0,5,8,8,3,8
%N Decimal expansion of Brun's quadruple primes constant.
%C Infinite sum of the reciprocals of p, p+2, p+6, and p+8, where p ranges over all elements of A007530.
%C The 9th digit is probably 0.
%H Thomas R. Nicely, <a href="https://faculty.lynchburg.edu/~nicely/quads/quads.html">Enumeration to 1.6e15 of the prime quadruplets</a>.
%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Brun's_theorem">Brun's theorem</a>.
%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Prime_quadruplet">Prime quadruplet</a>.
%F Sum_{n >= 1} (1/c(n) + 1/(c(n)+2) + 1/(c(n)+6) + 1/(c(n)+8)), where c(n) = A007530(n).
%e 0.8705883800[+-5]
%Y Cf. A007530, A194098, A194098, A065421.
%K nonn,cons,hard,more
%O 0,1
%A _Stanislav Sykora_, Jun 01 2012
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