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 A176055 #14 Feb 10 2025 12:02:41
%S A176055 2,1,1,8,0,3,3,9,8,8,7,4,9,8,9,4,8,4,8,2,0,4,5,8,6,8,3,4,3,6,5,6,3,8,
%T A176055 1,1,7,7,2,0,3,0,9,1,7,9,8,0,5,7,6,2,8,6,2,1,3,5,4,4,8,6,2,2,7,0,5,2,
%U A176055 6,0,4,6,2,8,1,8,9,0,2,4,4,9,7,0,7,2,0,7,2,0,4,1,8,9,3,9,1,1,3,7,4,8,4,7,5
%N A176055 Decimal expansion of (2+sqrt(5))/2.
%C A176055 Continued fraction expansion of (2+sqrt(5))/2 is A010698.
%C A176055 a(n) = A020837(n-1) for n > 1; a(1) = 2.
%H A176055 <a href="/index/Al#algebraic_02">Index entries for algebraic numbers, degree 2</a>.
%F A176055 Equals 1/2 + phi, with phi = A001622.
%F A176055 From _Amiram Eldar_, Jun 06 2021: (Start)
%F A176055 Equals 1 + Sum{k>=0} 1/(Fibonacci(2*k+1)+1).
%F A176055 Equals 1 + Sum{k>=0} binomial(2*k,k)/20^k. (End)
%e A176055 2.11803398874989484820...
%t A176055 RealDigits[GoldenRatio + 1/2, 10, 100][[1]] (* _Amiram Eldar_, Jun 06 2021 *)
%Y A176055 Cf. A002163 (sqrt(5)), A020837 (1/sqrt(80)), A010698 (repeat 2, 8).
%Y A176055 Cf. A000045, A001622.
%K A176055 cons,easy,nonn
%O A176055 1,1
%A A176055 _Klaus Brockhaus_, Apr 07 2010