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 A086258 #13 Oct 12 2019 19:07:58 %S A086258 0,14,26,46,83,118,309,194,414,538,786,958 %N A086258 a(n) is the smallest k such that 2^k+1 has n primitive prime factors. %C A086258 A prime factor of 2^n+1 is called primitive if it does not divide 2^r+1 for any r<n. See A086257 for the number of primitive prime factors in 2^n+1. It is known that a(8) = 194. %C A086258 Next term is > 666. - _David Wasserman_, Feb 25 2005 %D A086258 J. Brillhart et al., Factorizations of b^n +- 1. Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002. %H A086258 J. Brillhart et al., Factorizations of b^n +- 1 <a href="http://dx.doi.org/10.1090/conm/022">Available on-line</a> %e A086258 a(2) = 14 because 2^14+1 = 5*29*113 and 29 and 113 do not divide 2^r+1 for r < 14. %Y A086258 Cf. A086252, A086257. %K A086258 nonn,hard,more %O A086258 1,2 %A A086258 _T. D. Noe_, Jul 14 2003 %E A086258 More terms from _David Wasserman_, Feb 25 2005 %E A086258 a(11) from _D. S. McNeil_, Dec 19 2010 %E A086258 a(12) from _Amiram Eldar_, Oct 12 2019