A127998 Numbers n such that (24^n - 1)/23 is prime.

3, 5, 19, 53, 71, 653, 661, 10343, 49307, 115597, 152783

Offset

1,1

Comments

Note that 10343 was known to be a term of this sequence before 653 and 661. - Alonso del Arte, Mar 17 2014

Links

Table of n, a(n) for n=1..11.

H. Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927-930.

Henri Lifchitz, Mersenne and Fermat primes field

Index to primes in various ranges, form ((k+1)^n-1)/k

Mathematica

Select[Prime[Range[100]], PrimeQ[(24^# - 1)/23] &]

Prog

(PARI) isok(n) = isprime((24^n-1)/23); \\ Michel Marcus, Mar 13 2016

Crossrefs

Sequence in context: A148546 A148547 A360086 * A174132 A106918 A182357

Adjacent sequences: A127995 A127996 A127997 * A127999 A128000 A128001

Keyword

hard,more,nonn

Author

Alexander Adamchuk, Feb 11 2007

Extensions

a(6) and a(7) from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008

a(8) from Richard Fischer in 2004.

a(9) from Robert Price, Apr 18 2012

a(10) from Paul Bourdelais, Sep 12 2017

a(11) from Paul Bourdelais, Apr 09 2018

Status

approved