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 A247844 #12 Feb 16 2025 08:33:23
%S A247844 1,6,9,7,7,7,4,6,5,7,9,6,4,0,0,7,9,8,2,0,0,6,7,9,0,5,9,2,5,5,1,7,5,2,
%T A247844 5,9,9,4,8,6,6,5,8,2,6,2,9,9,8,0,2,1,2,3,2,3,6,8,6,3,0,0,8,2,8,1,6,5,
%U A247844 3,0,8,5,2,7,6,4,6,4,1,1,1,2,9,9,6,9,6,5,6,5,4,1,8,2,6,7,6,5,6,8,7,2,3,9,8
%N A247844 Decimal expansion of the value of the continued fraction [1; 1, 2, 3, 4, 5, ...].
%C A247844 Equals 1+A052119.
%H A247844 MathOverflow, <a href="http://mathoverflow.net/questions/177481">Is any particular algebraic number known to have unbounded continued fraction coefficients?</a>
%H A247844 Eric Weisstein's MathWorld, <a href="https://mathworld.wolfram.com/ContinuedFractionConstant.html">Continued Fraction Constant</a>
%H A247844 Eric Weisstein's MathWorld, <a href="https://mathworld.wolfram.com/ContinuedFraction.html">Continued Fraction</a>
%F A247844 1 + I_1(2) / I_0(2), where I_n(x) gives the modified Bessel function of the first kind.
%e A247844 1.697774657964007982006790592551752599486658262998...
%t A247844 FromContinuedFraction[Join[{1}, Range[50]]] // RealDigits[#, 10, 105]& // First
%t A247844 (* or *) 1+BesselI[1, 2]/BesselI[0, 2] // RealDigits[#, 10, 105]& // First
%o A247844 (PARI) 1+besseli(1,2)/besseli(0,2) \\ _Charles R Greathouse IV_, Oct 23 2023
%Y A247844 Cf. A001040, A001053, A052119, A060997, A070910, A096789.
%K A247844 nonn,cons
%O A247844 1,2
%A A247844 _Jean-François Alcover_, Sep 25 2014