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 A187798 #49 Nov 28 2024 15:04:52
%S A187798 6,9,0,9,8,3,0,0,5,6,2,5,0,5,2,5,7,5,8,9,7,7,0,6,5,8,2,8,1,7,1,8,0,9,
%T A187798 4,1,1,3,9,8,4,5,4,1,0,0,9,7,1,1,8,5,6,8,9,3,2,2,7,5,6,8,8,6,4,7,3,6,
%U A187798 9,7,6,8,5,9,0,5,4,8,7,7,5,1,4,6,3,9,6,3,9,7,9,0,5,3,0,4,4,3,1,2,5,7,6,2,2
%N A187798 Decimal expansion of (3-phi)/2, where phi is the golden ratio.
%C A187798 This is the height h of the isosceles triangle in a regular pentagon inscribed in the unit circle formed from a diagonal as base and two adjacent pentagon sides. h = sqrt(sqrt(3-phi)^2 - (sqrt(2 + phi)/2)^2) = sqrt(10 - 5*phi)/2 = (3 - phi)/2. - _Wolfdieter Lang_, Jan 07 2018
%H A187798 Ivan Panchenko, <a href="/A187798/b187798.txt">Table of n, a(n) for n = 0..1000</a>
%H A187798 <a href="/index/Al#algebraic_02">Index entries for algebraic numbers, degree 2</a>.
%F A187798 Equals (3-phi)/2 = A094874/2 with phi from A001622.
%F A187798 From _Amiram Eldar_, Nov 28 2024: (Start)
%F A187798 Equals 1/A344212.
%F A187798 Equals Product_{k>=0} (1 - 1/A081011(k)). (End)
%e A187798 0.6909830056250525758977065828171809411398454100971185689322756886473697685905...
%t A187798 RealDigits[(3 - GoldenRatio)/2, 10, 111][[1]] (* or *)
%t A187798 RealDigits[(5 - Sqrt[5])/4, 10, 111][[1]] (* _Robert G. Wilson v_, Jan 07 2018 *)
%o A187798 (PARI) (5-sqrt(5))/4 \\ _Charles R Greathouse IV_, Aug 31 2013
%Y A187798 Cf. A001622, A081011, A187426, A226765, A094874, A344212.
%K A187798 nonn,cons
%O A187798 0,1
%A A187798 _Joost Gielen_, Aug 30 2013
%E A187798 Extended by _Charles R Greathouse IV_, Aug 31 2013