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 A215058 #17 Aug 11 2020 01:26:47 %S A215058 0,0,7,25,242,1933,16080,139921,1234958 %N A215058 Number of primes of the form 1 + b^128 for 1 < b < 10^n. %C A215058 Primes 1 + b^128 are a form of generalized Fermat primes. %C A215058 It is conjectured that a(n) is asymptotic to 0.0242888*li(10^n) %H A215058 Yves Gallot, <a href="http://yves.gallot.pagesperso-orange.fr/primes/results.html">Status of the smallest base values yielding Generalized Fermat primes</a> %H A215058 Yves Gallot, <a href="http://yves.gallot.pagesperso-orange.fr/primes/stat.html">How many prime numbers appear in a sequence ?</a> %H A215058 Yves Gallot, <a href="http://yves.gallot.pagesperso-orange.fr/papers/ccdgfpn.html">A Problem on the Conjecture Concerning the Distribution of Generalized Fermat Prime numbers (a new method for the search for large primes)</a> %e A215058 a(3) = 7 because the generalized Fermat numbers F_7(b) where b<10^3 are prime only for b: 120, 190, 234, 506, 532, 548, 960. %o A215058 (PARI) a(n) = sum(b=1, 10^n/2-1, isprime((2*b)^128+1)) %Y A215058 Cf. A215047, A215048, A215049, A215050, A215051, A215057. %K A215058 nonn,more %O A215058 1,3 %A A215058 _Henryk Dabrowski_, Aug 01 2012 %E A215058 a(8)-a(9) from _Kellen Shenton_, Aug 10 2020