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 A247860 #8 Sep 29 2014 14:40:15
%S A247860 4,5,5,0,2,5,6,9,9,8,0,1,9,9,4,6,8,7,1,8,0,2,0,2,1,0,2,6,3,8,0,8,4,2,
%T A247860 1,8,9,8,1,3,7,6,8,7,9,4,7,6,3,5,0,6,6,1,9,7,1,4,2,4,6,4,2,7,6,2,5,0,
%U A247860 5,6,7,0,6,6,5,5,8,1,8,7,3,7,5,6,6,2,3,9,2,4,4,9,5,9,7,6,0,8,6,8,7,5,6
%N A247860 Decimal expansion of the value of the continued fraction [0; 2, 5, 17, 37, 101, 197, ...], generated with primes of the form n^2 + 1.
%H A247860 Marek Wolf, <a href="http://arxiv.org/abs/1003.4015">Continued fractions constructed from prime numbers</a>, arxiv.org/abs/1003.4015, p. 11.
%e A247860 1/(2 + 1/(5 + 1/(17 + 1/(37 + 1/(101 + 1/(197 + 1/(257 + 1/(401 + ...))))))))
%e A247860 0.45502569980199468718020210263808421898137687947635...
%t A247860 pp = Select[Range[100]^2 + 1, PrimeQ]; RealDigits[FromContinuedFraction[Join[{0}, pp]], 10, 103] // First
%Y A247860 Cf. A002496, A199401, A247858.
%K A247860 nonn,cons
%O A247860 0,1
%A A247860 _Jean-François Alcover_, Sep 25 2014