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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.

T. 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: A051762 A247017 A198112 * A155094 A294969 A292821

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 24 00:30 EDT 2018. Contains 315306 sequences. (Running on oeis4.)