This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A233009 #37 Oct 15 2024 04:31:16 %S A233009 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, %T A233009 15,16,11,6,6,1,15,9,7,21,5,5,3,1,19,21,22,6,6,7,6,3 %N A233009 Exponents p of the Mersenne primes 2^p - 1 (see A000043) read mod 23. %H A233009 Chris K. Caldwell, <a href="http://www.utm.edu/research/primes/largest.html#largest">Recent Mersenne primes</a>. %H A233009 Walter Wegscheider, <a href="http://www.austromath.at/mersenne/mersenne-primzahlen.html">Liste der Mersenne-Primzahlen</a>, Pädagogische Hochschule für Niederösterreich (in German). %F A233009 a(n) = A000043(n) mod 23. %e A233009 For n = 9, the 9th Mersenne prime index is A000043(9) = 61 and a(9) = 61 mod 23 = 15. %t A233009 Array[ Mod[ MersennePrimeExponent@#, 23] &, 44] (* _Robert G. Wilson v_, Aug 06 2018 *) %Y A233009 Cf. A000043, A126043-A126059, A233008. %K A233009 nonn,more,less %O A233009 1,1 %A A233009 _Freimut Marschner_, Dec 03 2013 %E A233009 a(46)-a(47) corrected and a(48) removed by _Gord Palameta_, Aug 06 2018 %E A233009 a(48) from _Amiram Eldar_, Oct 15 2024