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 A247858 #10 Dec 11 2020 11:32:28
%S A247858 4,5,5,0,2,4,8,1,6,4,9,0,1,7,0,0,2,2,3,6,9,0,5,2,8,0,8,2,7,9,7,4,4,8,
%T A247858 2,4,1,0,5,7,5,5,5,4,8,9,0,5,0,7,6,4,4,0,5,6,8,5,4,1,8,5,9,1,5,0,8,4,
%U A247858 6,0,8,5,0,1,0,7,1,8,6,3,1,4,3,6,3,1,0,6,6,7,6,9,7,5,4,6,0,4,5,1,9,9,2
%N A247858 Decimal expansion of the value of the continued fraction [0; 2, 5, 17, 17, 37, 41, 97, 97, ...], generated with primes of the form a^2 + b^4.
%H A247858 John Friedlander and Henryk Iwaniec, <a href="https://doi.org/10.1073/pnas.94.4.1054">Using a parity-sensitive sieve to count prime values of a polynomial</a>, PNAS February 18, 1997 94 (4) 1054-1058.
%H A247858 Wikipedia, <a href="http://en.wikipedia.org/wiki/Friedlander%E2%80%93Iwaniec_theorem">Friedlander-Iwaniec theorem</a>
%H A247858 Marek Wolf, <a href="http://arxiv.org/abs/1003.4015">Continued fractions constructed from prime numbers</a>, arXiv:1003.4015 [math.NT], 2010, pp. 8-9.
%e A247858 1/(2 + 1/(5 + 1/(17 + 1/(17 + 1/(37 + 1/(41 + 1/(97 + 1/(97 + ...))))))))
%e A247858 0.45502481649017002236905280827974482410575554890507644...
%t A247858 max = 1000; r = Reap[Do[n = a^2 + b^4; If[n <= max && PrimeQ[n], Sow[n]], {a, Sqrt[max]}, {b, max^(1/4)}]][[2, 1]]; u = Union[r, SameTest -> (False&)] ; RealDigits[FromContinuedFraction[Join[{0}, u]], 10, 103] // First
%Y A247858 Cf. A028916, A243340, A247857.
%K A247858 nonn,cons
%O A247858 0,1
%A A247858 _Jean-François Alcover_, Sep 25 2014