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.

Showing 1-2 of 2 results.

A163795 a(n) is the n-th J_15-prime (Josephus_15 prime).

Original entry on oeis.org

3, 9, 13, 25, 49, 361, 961, 1007, 2029, 8593, 24361, 44795, 88713
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 15th unmarked number until all N numbers are marked. The order in which the N numbers are marked defines a permutation; N is a J_15-prime if this permutation consists of a single cycle of length N.
There are 13 J_15-primes in the interval 2..1000000 only. No formula is known; the J_15-primes have been found by exhaustive search.

Examples

			All J_15-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 A163794 for J_2- through J_14-primes.
Cf. A163796 through A163800 for J_16- through J_20-primes.

A163797 a(n) is the n-th J_17-prime (Josephus_17 prime).

Original entry on oeis.org

3, 5, 7, 39, 93, 267, 557, 2389, 2467, 4059, 4681, 6213, 70507, 151013, 282477, 421135, 1272901
Offset: 1

Views

Author

Peter R. J. Asveld, Aug 04 2009

Keywords

Comments

Place the numbers 1..N (N>=2) on a circle and cyclicly mark the 17th unmarked number until all N numbers are marked. The order in which the N numbers are marked defines a permutation; N is a J_17-prime if this permutation consists of a single cycle of length N.
There are 16 J_17-primes in the interval 2..1000000 only. No formula is known; the J_17-primes have been found by exhaustive search.

Examples

			All J_17-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 A163796 for J_2- through J_16-primes.
Cf. A163798 through A163800 for J_18- through J_20-primes.

Extensions

a(17) from Jinyuan Wang, Jul 05 2025
Showing 1-2 of 2 results.