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 A187799 #50 Jan 05 2025 19:51:39
%S A187799 7,6,3,9,3,2,0,2,2,5,0,0,2,1,0,3,0,3,5,9,0,8,2,6,3,3,1,2,6,8,7,2,3,7,
%T A187799 6,4,5,5,9,3,8,1,6,4,0,3,8,8,4,7,4,2,7,5,7,2,9,1,0,2,7,5,4,5,8,9,4,7,
%U A187799 9,0,7,4,3,6,2,1,9,5,1,0,0,5,8,5,5,8,5,5,9,1,6,2,1,2,1,7,7,2,5,0,3,0,4,9,1,8,2,3,8,4,9
%N A187799 Decimal expansion of 20/phi^2, where phi is the golden ratio. Also (with a different offset), decimal expansion of 3 - sqrt(5).
%H A187799 Ivan Panchenko, <a href="/A187799/b187799.txt">Table of n, a(n) for n = 1..1000</a>
%H A187799 Mohammad K. Azarian, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Problems/ElemProbAugust2013.pdf">The Value of a Series of Reciprocal Fibonacci Numbers, Problem B-1133</a>, Fibonacci Quarterly, Vol. 51, No. 3, August 2013, p. 275; <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Problems/ElemProbSolnAug14.pdf">Solution</a> published in Vol. 52, No. 3, August 2014, pp. 277-278.
%F A187799 10*(3 - sqrt(5)) = 30 - 10*sqrt(5) = (5 - sqrt(5))^2 = 20/phi^2.
%F A187799 2 * Sum_{i > 1} (-1)^i/(F(i)F(i + 1)) = 3 - sqrt(5), where F(i) is the i-th Fibonacci number. This formula comes from John D. Watson, Jr.'s solution to Azarian's Problem B-1133 in the Fibonacci Quarterly. Azarian originally posed the problem as an infinite alternating sum explicitly written out for the first dozen terms or so. See the Azarian links above. - _Alonso del Arte_, Aug 25 2016
%e A187799 20/phi^2 = 7.6393202250021030359082633...
%e A187799 3 - sqrt(5) = 0.76393202250021030359082633... (with offset 0).
%t A187799 First@ RealDigits[N[5*(Sqrt[5] - 1)^2, 111]] (* _Michael De Vlieger_, Feb 25 2015 *)
%o A187799 (PARI) 5*(sqrt(5)-1)^2 \\ _Charles R Greathouse IV_, Aug 31 2013
%o A187799 (Magma) 5*(Sqrt(5)-1)^2; // _Vincenzo Librandi_, Feb 24 2015
%Y A187799 Cf. A187426, A187798, A094874.
%K A187799 nonn,cons
%O A187799 1,1
%A A187799 _Joost Gielen_, Aug 30 2013
%E A187799 Extended by _Charles R Greathouse IV_, Aug 31 2013