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 A139346 #15 Feb 07 2022 08:18:20
%S A139346 0,4,7,2,2,0,0,9,6,2,5,4,3,5,9,8,3,3,7,6,6,8,7,8,6,9,4,0,4,8,7,9,4,5,
%T A139346 6,5,4,9,5,5,4,8,9,9,4,7,2,7,3,4,2,7,8,1,3,2,8,1,8,2,1,9,8,2,7,8,3,5,
%U A139346 3,3,0,1,1,6,7,0,6,3,5,9,5,5,6,3,6,8,1,2,3,8,9,8,2,3,3,2,2,6,0,5,3,2,2,8
%N A139346 Decimal expansion of cosine of the golden ratio, negated. That is, the decimal expansion of -cos((1+sqrt(5))/2).
%C A139346 By the Lindemann-Weierstrass theorem, this constant is transcendental. - _Charles R Greathouse IV_, May 13 2019
%H A139346 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%F A139346 Equals 1/A139349. - _Amiram Eldar_, Feb 07 2022
%e A139346 -0.04722009625435983376687869404879456549554899472734...
%t A139346 Join[{0}, RealDigits[Cos[GoldenRatio], 10, 100][[1]]] (* _Amiram Eldar_, Feb 07 2022 *)
%o A139346 (PARI) -cos((1+sqrt(5))/2) \\ _Charles R Greathouse IV_, May 13 2019
%Y A139346 Cf. A001622, A094214, A104457, A098317, A002390, A139339, A139340, A139341, A139342, A139345, A139349.
%K A139346 nonn,cons
%O A139346 0,2
%A A139346 _Mohammad K. Azarian_, Apr 15 2008
%E A139346 Edited by _N. J. A. Sloane_, Dec 11 2008