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.

A163793 a(n) is the n-th J_13-prime (Josephus_13 prime).

Original entry on oeis.org

5, 57, 117, 187, 251, 273, 275, 665, 2511, 40393, 48615, 755921, 970037
Offset: 1

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Author

Peter R. J. Asveld, Aug 04 2009

Keywords

Comments

Place the numbers 1..N (N>=2) on a circle and cyclicly mark the 13th unmarked number until all N numbers are marked. The order in which the N numbers are marked defines a permutation; N is a J_13-prime if this permutation consists of a single cycle of length N.
There are 13 J_13-primes in the interval 2..1000000 only. No formula is known; the J_13-primes have been found by exhaustive search.

Examples

			All J_13-primes are odd.
		

References

  • R. L. Graham, D. E. Knuth & O. Patashnik, Concrete Mathematics (1989), Addison-Wesley, Reading, MA. Sections 1.3 & 3.3.

Crossrefs

Cf. A163782 through A163792 for J_2- through J_12-primes.
Cf. A163794 through A163800 for J_14- through J_20-primes.