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 A213007 Decimal expansion of Brun's quadruple primes constant. 2
 8, 7, 0, 5, 8, 8, 3, 8 (list; constant; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Infinite sum of the reciprocals of p, p+2, p+6, and p+8, where p ranges over all elements of A007530. The 9th digit is probably 0. LINKS Table of n, a(n) for n=0..7. Thomas R. Nicely, Enumeration to 1.6e15 of the prime quadruplets. Wikipedia, Brun's theorem. Wikipedia, Prime quadruplet. FORMULA Sum_{n >= 1} (1/c(n) + 1/(c(n)+2) + 1/(c(n)+6) + 1/(c(n)+8)), where c(n) = A007530(n). EXAMPLE 0.8705883800[+-5] CROSSREFS Cf. A007530, A194098, A194098, A065421. Sequence in context: A330142 A198112 A358938 * A155094 A369633 A294969 Adjacent sequences: A213004 A213005 A213006 * A213008 A213009 A213010 KEYWORD nonn,cons,hard,more AUTHOR Stanislav Sykora, Jun 01 2012 STATUS approved

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Last modified September 10 23:44 EDT 2024. Contains 375795 sequences. (Running on oeis4.)