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.

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