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
Offset: 1
Examples
For n = 9, the 9th Mersenne prime index is A000043(9) = 61 and a(9) = 61 mod 23 = 15.
Links
- Chris K. Caldwell, Recent Mersenne primes.
- Walter Wegscheider, Liste der Mersenne-Primzahlen, Pädagogische Hochschule für Niederösterreich (in German).
Programs
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Mathematica
Array[ Mod[ MersennePrimeExponent@#, 23] &, 44] (* Robert G. Wilson v, Aug 06 2018 *)
Formula
a(n) = A000043(n) mod 23.
Extensions
a(46)-a(47) corrected and a(48) removed by Gord Palameta, Aug 06 2018
a(48) from Amiram Eldar, Oct 15 2024