A213007 Decimal expansion of Brun's quadruple primes constant.

8, 7, 0, 5, 8, 8, 3, 8

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.

References

Steven R. Finch, Mathematical Constants, Encyclopedia of Mathematics and its Applications, vol. 94, Cambridge University Press, 2003, Section 2.14, p. 133.

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