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 A344212 #18 Feb 04 2025 10:43:48
%S A344212 1,4,4,7,2,1,3,5,9,5,4,9,9,9,5,7,9,3,9,2,8,1,8,3,4,7,3,3,7,4,6,2,5,5,
%T A344212 2,4,7,0,8,8,1,2,3,6,7,1,9,2,2,3,0,5,1,4,4,8,5,4,1,7,9,4,4,9,0,8,2,1,
%U A344212 0,4,1,8,5,1,2,7,5,6,0,9,7,9,8,8,2,8,8,2,8,8,1,6,7
%N A344212 Decimal expansion of 1 + 1/sqrt(5).
%C A344212 Decimal expansion of the midradius of a rhombic triacontahedron with unit edge length.
%C A344212 Essentially the same sequence of digits as A176453, A134974, A020762 and A010476. - _R. J. Mathar_, May 16 2021
%H A344212 Wikipedia, <a href="https://en.wikipedia.org/wiki/Rhombic_triacontahedron">Rhombic triacontahedron</a>.
%H A344212 <a href="/index/Al#algebraic_02">Index entries for algebraic numbers, degree 2</a>.
%F A344212 From _Amiram Eldar_, Nov 28 2024: (Start)
%F A344212 Equals 2*A242671 = 1/A187798.
%F A344212 Equals Product_{k>=0} (1 + 1/A081005(k)). (End)
%e A344212 1.447213595499957939281834733746255247088123671922305...
%t A344212 RealDigits[1 + 1/Sqrt[5], 10, 100][[1]] // Flatten
%o A344212 (PARI) 5^-.5+1 \\ _Charles R Greathouse IV_, Feb 04 2025
%o A344212 (PARI) polrootsreal(5*x^2-10*x+4)[2] \\ _Charles R Greathouse IV_, Feb 04 2025
%Y A344212 Cf. A019952 (rhombic triacontahedron inscribed sphere radius).
%Y A344212 Cf. A344171 (rhombic triacontahedron surface area).
%Y A344212 Cf. A344172 (rhombic triacontahedron volume).
%Y A344212 Cf. A010476, A020762, A081005, A134974, A176453, A187798, A242671.
%K A344212 nonn,cons
%O A344212 1,2
%A A344212 _Wesley Ivan Hurt_, May 11 2021