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 A215049 #25 Aug 13 2012 16:19:11
%S A215049 2,2,40,335,2498,20886,174368,1507722,13300713
%N A215049 Number of primes of the form 1 + b^8 for 1 < b < 10^n.
%C A215049 Primes 1 + b^8 are a form of generalized Fermat primes. It is conjectured that a(n) is asymptotic to 0.261599*li(10^n).
%H A215049 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 A215049 Yves Gallot, <a href="http://yves.gallot.pagesperso-orange.fr/primes/stat.html">How many prime numbers appear in a sequence ?</a>
%H A215049 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>
%F A215049 a(n) = A214454(8*n) - 1.
%e A215049 a(1) = 2 because the only Fermat primes F_3(b) where b<10^1 are the primes: 257, 65537.
%t A215049 Table[Length[Select[Range[2,10^n-1]^8 + 1, PrimeQ]], {n, 5}] (* _T. D. Noe_, Aug 01 2012 *)
%o A215049 (PARI) a(n) = sum(b=1, 10^n/2-1, isprime((2*b)^8+1))
%Y A215049 Cf. A214454.
%K A215049 nonn
%O A215049 1,1
%A A215049 _Henryk Dabrowski_, Aug 01 2012