A242200 Numbers n such that n*7^n - 1 is prime.

2, 18, 68, 84, 3812, 14838, 51582

Offset

1,1

Links

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

Steven Harvey, Generalized Woodall Search

Mathematica

Select[Range[2000], PrimeQ[# 7^# - 1] &]

Prog

(Magma) [n: n in [0..3000] | IsPrime(n*7^n-1)];
(PARI) is(n)=ispseudoprime(n*7^n-1) \\ Charles R Greathouse IV, May 22 2017

Crossrefs

Cf. numbers n such that n*k^n - 1 is prime. A002234 (k=2), A006553 (k=3), A086661 (k=4), A059676 (k=5), A059675 (k=6), this sequence (k=7), A242201 (k=8), A242202 (k=9), A059671 (k=10).

Sequence in context: A232155 A368755 A112365 * A258929 A034959 A316902

Adjacent sequences: A242197 A242198 A242199 * A242201 A242202 A242203

Keyword

nonn,more

Author

Vincenzo Librandi, May 09 2014

Extensions

a(5) - a(7) from Harvey's list (see Links).

Status

approved