

A258357


Numbers n such that cyclotomic polynomial value Phi(7,n!) is prime.


1




OFFSET

1,3


COMMENTS

Except for the values 0,1,2 and 3, terms correspond to probable primes.
a(8) > 6502.
Also, numbers n such that n! belongs to A100330.  Michel Marcus, May 30 2015


LINKS

Table of n, a(n) for n=1..7.


EXAMPLE

3 is in the sequence because Phi(7,3!) = 1 + 6 + 6^2 + 6^3 + 6^4 + 6^5 + 6^6 = 55987 is prime.


MATHEMATICA

Select[Range[0, 6502], PrimeQ[Cyclotomic[7, #!]] &]


CROSSREFS

Cf. A002981, A002982, A046029, A200906.
Sequence in context: A090100 A270314 A132484 * A160858 A062648 A094003
Adjacent sequences: A258354 A258355 A258356 * A258358 A258359 A258360


KEYWORD

nonn,more


AUTHOR

Robert Price, May 27 2015


STATUS

approved



