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 A002185 M2233 N0885 #27 Feb 25 2025 23:16:39 %S A002185 3,1,11,43,19,683,2731,331,43691,174763,5419,2796203,251,87211,59, %T A002185 715827883,67,281,1777,22366891,83,2932031007403,18837001,283, %U A002185 4363953127297,307,107,2971,571,2833,768614336404564651,77158673929,131,7327657,139,56409643,1753 %N A002185 Smallest primitive factor of 2^(2n+1) + 1. %D A002185 J. Brillhart et al., Factorizations of b^n +- 1. Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 2nd edition, 1985; and later supplements. %D A002185 M. Kraitchik, Recherches sur la Théorie des Nombres. Gauthiers-Villars, Paris, Vol. 1, 1924, Vol. 2, 1929, see Vol. 2, p. 85. %D A002185 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). %D A002185 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A002185 Max Alekseyev, <a href="/A002185/b002185.txt">Table of n, a(n) for n = 0..568</a> %H A002185 J. Brillhart et al., <a href="http://dx.doi.org/10.1090/conm/022">Factorizations of b^n +- 1</a>, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002. %H A002185 S. S. Wagstaff, Jr., <a href="http://www.cerias.purdue.edu/homes/ssw/cun/index.html">The Cunningham Project</a> %Y A002185 Cf. A002589, A086257, A112927. %K A002185 nonn %O A002185 0,1 %A A002185 _N. J. A. Sloane_ %E A002185 Terms a(25) onward from _Max Alekseyev_, Oct 16 2022