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 A215698 #5 Aug 22 2012 21:06:15 %S A215698 0,0,4,30,272,2322 %N A215698 Number of primes of the form 1 + b^256 for 1 < b < 10^n. %C A215698 Primes 1 + b^256 are a form of generalized Fermat primes. %C A215698 It is conjectured that a(n) is asymptotic to 0.0290422*li(10^n) %H A215698 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 A215698 Yves Gallot, <a href="http://yves.gallot.pagesperso-orange.fr/primes/stat.html">How many prime numbers appear in a sequence ?</a> %H A215698 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 A215698 a(3) = 4 because the generalized Fermat numbers F_8(b) where b<10^3 are prime only for b: 278, 614, 892, 898. %o A215698 (PARI) a(n) = sum(b=1, 10^n/2-1, isprime((2*b)^256+1)) %Y A215698 Cf. A215047, A215048, A215049, A215050, A215051, A215057, A215058. %K A215698 nonn %O A215698 1,3 %A A215698 _Henryk Dabrowski_, Aug 21 2012