

A163785


a(n) is the nth J_5prime (Josephus_5 prime).


2



3, 15, 17, 45, 73, 83, 165, 177, 181, 229, 377, 383, 787, 2585, 3127, 3635, 4777, 36417, 63337, 166705, 418411
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OFFSET

1,1


COMMENTS

Place the numbers 1..N (N>=2) on a circle and cyclicly mark the 5th unmarked number until all N numbers are marked. The order in which the N numbers are marked defines a permutation; N is a J_5prime if this permutation consists of a single cycle of length N.
There are 21 J_5primes in the interval 2..1000000 only. No formula is known; the J_5primes have been found by exhaustive search.


REFERENCES

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


LINKS



EXAMPLE

All J_5primes are odd.


CROSSREFS



KEYWORD

nonn,more


AUTHOR



STATUS

approved



