cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A155463 Largest element of a set of n primes with the property that the pairwise averages are all distinct primes, having the smallest largest element (A115631).

Original entry on oeis.org

7, 19, 71, 173, 383, 881, 2111, 5417, 10691, 21757, 27611
Offset: 2

Views

Author

Dmitry Kamenetsky, Jan 22 2009

Keywords

Comments

The solution for n=5 is {5, 29, 53, 89, 173}, so a(5)=173. This sequence is not proved to be optimal, so smaller terms may exist.

Crossrefs

A113832 Triangle read by rows: row n (n>=2) gives a set of n primes with the property that the pairwise averages are all primes, having the smallest largest element.

Original entry on oeis.org

3, 7, 3, 7, 19, 3, 11, 23, 71, 5, 29, 53, 89, 113, 3, 11, 83, 131, 251, 383, 5, 29, 113, 269, 353, 449, 509, 5, 17, 41, 101, 257, 521, 761, 881, 23, 431, 503, 683, 863, 1091, 1523, 1871, 2963, 31, 1123, 1471, 1723, 3463, 3571, 4651, 5563, 5743, 6991
Offset: 2

Views

Author

N. J. A. Sloane, Jan 25 2006

Keywords

Comments

If there is more than one set with the same smallest last element, choose the lexicographically earliest solution.
For distinct primes, the solution for n=5 is {5, 29, 53, 89, 173}.

Examples

			Triangle begins:
3, 7
3, 7, 19
3, 11, 23, 71
5, 29, 53, 89, 113
3, 11, 83, 131, 251, 383
5, 29, 113, 269, 353, 449, 509
The set of primes generated by {5, 29, 53, 89, 113} is {17, 29, 41, 47, 59, 59, 71, 71, 83, 101}.
		

References

  • Antal Balog, The prime k-tuplets conjecture on average, in "Analytic Number Theory" (eds. B. C. Berndt et al.) Birkhäuser, Boston, 1990, pp. 165-204. [Background]

Crossrefs

See A115631 for the case when all pairwise averages are distinct primes.

Extensions

More terms from T. D. Noe, Feb 01 2006
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