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.

A163784 a(n) is the n-th J_4-prime (Josephus_4 prime).

Original entry on oeis.org

2, 5, 10, 369, 609, 1841, 2462, 3297, 3837, 14945, 94590, 98121, 965013, 1634157
Offset: 1

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Author

Peter R. J. Asveld, Aug 05 2009

Keywords

Comments

Place the numbers 1..N (N>=2) on a circle and cyclicly mark the 4th unmarked number until all N numbers are marked. The order in which the N numbers are marked defines a permutation; N is a J_4-prime if this permutation consists of a single cycle of length N.
There are 13 J_4-primes in the interval 2..1000000 only. No formula is known; the J_4-primes have been found by exhaustive search.
a(15) > 3*10^6. - Bert Dobbelaere, Apr 20 2019

Examples

			2 is a J_4-prime (trivial).
		

References

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

Crossrefs

A163782 through A163783 for J_2- through J_3-primes. A163785 through A163800 for J_5- through J_20-primes.

Extensions

a(14) from Bert Dobbelaere, Apr 20 2019

A163786 a(n) is the n-th J_6-prime (Josephus_6 prime).

Original entry on oeis.org

2, 13, 17, 18, 34, 49, 93, 97, 106, 225, 401, 745, 2506, 3037, 3370, 4713, 5206, 8585, 13418, 32237, 46321, 75525, 97889, 106193, 238513, 250657, 401902, 490118
Offset: 1

Views

Author

Peter R. J. Asveld, Aug 05 2009

Keywords

Comments

Place the numbers 1..N (N>=2) on a circle and cyclicly mark the 6th unmarked number until all N numbers are marked. The order in which the N numbers are marked defines a permutation; N is a J_6-prime if this permutation consists of a single cycle of length N.
There are 28 J_6-primes in the interval 2..1000000 only. No formula is known; the J_6-primes were found by exhaustive search.

Examples

			2 is a J_6-prime (trivial).
		

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 A163785 for J_2- through J_5-primes.
Cf. A163787 through A163800 for J_7- through J_20-primes.
Showing 1-2 of 2 results.