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%I #34 Jan 24 2025 09:42:10
%S 2,0,7,1,0,6,7,8,1,1,8,6,5,4,7,5,2,4,4,0,0,8,4,4,3,6,2,1,0,4,8,4,9,0,
%T 3,9,2,8,4,8,3,5,9,3,7,6,8,8,4,7,4,0,3,6,5,8,8,3,3,9,8,6,8,9,9,5,3,6,
%U 6,2,3,9,2,3,1,0,5,3,5,1,9,4,2,5,1,9,3
%N Decimal expansion of (sqrt(2) - 1)/2.
%C This is the maximum increase in mass-energy a particle can carry away from a neutral rotating (Kerr) black hole via the Penrose process.
%C Apart from leading digits the same as A174968, A157214 and A010503. - _R. J. Mathar_, Feb 24 2016
%D Subrahmanyan Chandrasekhar, The Mathematical Theory of Black Holes, Oxford (1983), pp. 368-369.
%H G. C. Greubel, <a href="/A268683/b268683.txt">Table of n, a(n) for n = 0..10000</a>
%H Stijn J. van Tongeren, <a href="http://www.staff.science.uu.nl/~proko101/StijnJvanTongeren_bh3.pdf">Rotating black holes</a> (2009).
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Penrose_process">Penrose process</a>
%H <a href="/index/Al#algebraic_02">Index entries for algebraic numbers, degree 2</a>.
%e 0.20710678118654752440084436210484903928483593768847403658833986899536623...
%t RealDigits[(Sqrt[2] - 1) / 2, 10, 90] [[1]] (* _Vincenzo Librandi_, Feb 20 2016 *)
%o (PARI) (sqrt(2)-1)/2
%o (Magma) (Sqrt(2)-1)/2; // _Vincenzo Librandi_, Feb 20 2016
%Y Cf. A268682, A174968.
%K nonn,cons,easy,changed
%O 0,1
%A _Charles R Greathouse IV_, Feb 19 2016
%E More digits from _Jon E. Schoenfield_, Mar 15 2018