A233009 - OEIS

A233009

Exponents p of the Mersenne primes 2^p - 1 (see A000043) read mod 23.

2, 3, 5, 7, 13, 17, 19, 8, 15, 20, 15, 12, 15, 9, 14, 18, 4, 20, 21, 7, 6, 5, 12, 19, 12, 2, 15, 16, 11, 6, 6, 1, 15, 9, 7, 21, 5, 5, 3, 1, 19, 21, 22, 6, 6, 7, 6, 3

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Table of n, a(n) for n=1..48.

Chris K. Caldwell, Recent Mersenne primes.

Walter Wegscheider, Liste der Mersenne-Primzahlen, Pädagogische Hochschule für Niederösterreich (in German).

FORMULA

a(n) = A000043(n) mod 23.

EXAMPLE

For n = 9, the 9th Mersenne prime index is A000043(9) = 61 and a(9) = 61 mod 23 = 15.

MATHEMATICA

Array[ Mod[ MersennePrimeExponent@#, 23] &, 44] (* Robert G. Wilson v, Aug 06 2018 *)

CROSSREFS

Cf. A000043, A126043-A126059, A233008.

Sequence in context: A126059 A126058 A233008 * A243535 A308078 A050757

Adjacent sequences: A233006 A233007 A233008 * A233010 A233011 A233012

KEYWORD

nonn,more,less

AUTHOR

Freimut Marschner, Dec 03 2013

EXTENSIONS

a(46)-a(47) corrected and a(48) removed by Gord Palameta, Aug 06 2018

a(48) from Amiram Eldar, Oct 15 2024

STATUS

approved