A146214 a(n) = (10^n)-th lower twin prime.

3, 107, 3821, 79559, 1260989, 18409199, 252427601, 3285916169, 41375648687, 507575862527, 6100479510551

Offset

0,1

Comments

The Gcc with Gmp program is at the bottom of the link. The link also has a PARI bisection algorithm which gives a very good approximation for the n-th prime number and the n-th twin prime number. For example the 10^10-th lower twin prime approximation is 6100475249386, this has a relative error of 0.000000698... from the actual a(10) above.

The (10^n)-th upper twin prime is given as a(n)+2 = (5,109,3823,79561, 1260991,18409201,252427603,...). - M. F. Hasler, Dec 06 2008

Links

Table of n, a(n) for n=0..10.

Cino Hilliard, Approximating the n-th lower twin prime (broken link)

Formula

a(n) = A001359(10^n). - M. F. Hasler, Dec 06 2008

Example

For n=1, the first 10 lower twin primes (A001359) are: 3,5,11,17,29,41,59,71,101,107. So a(1) = 107 is the 10th lower twin prime.

Crossrefs

Cf. A001097, A001359, A147797.

Sequence in context: A023325 A094200 A003705 * A261997 A362056 A061308

Adjacent sequences: A146211 A146212 A146213 * A146215 A146216 A146217

Keyword

nonn,more

Author

Cino Hilliard, Oct 28 2008

Extensions

a(0) from Zak Seidov, Oct 29 2008

Edited and cross-references added by M. F. Hasler, Dec 06 2008

Status

approved