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%I A019798 #26 Jul 08 2023 04:06:23
%S A019798 2,3,3,1,6,4,3,9,8,1,5,9,7,1,2,4,2,0,3,3,6,3,5,3,6,0,6,2,1,6,8,4,0,0,
%T A019798 8,7,6,3,8,0,2,3,6,2,9,9,1,8,7,5,8,8,4,2,3,0,0,8,0,9,6,4,4,7,7,7,6,0,
%U A019798 1,0,0,4,9,4,1,2,6,5,7,3,4,9,5,0,2,6,2,9,9,9,1,7,9,5,4,7,7,7,5
%N A019798 Decimal expansion of sqrt(2*e).
%C A019798 The coefficient a for which y=a*sqrt(x) kisses the exponential function y=exp(x). The kissing point is (0.5, sqrt(e)). For more details, see A257776. Also, inverse of this constant equals the maximum value of sqrt(x)*exp(-x) for positive x, attained at x=1/2. - _Stanislav Sykora_, Nov 04 2015
%H A019798 Ivan Panchenko, <a href="/A019798/b019798.txt">Table of n, a(n) for n = 1..1000</a>
%H A019798 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%F A019798 From _Amiram Eldar_, Jul 08 2023: (Start)
%F A019798 Equals Product_{n>=0} (e / (1 + 1/(n-1/2))^n).
%F A019798 Equals Product_{n>=0} (e * (1 - 1/(n+1/2))^n). (End)
%e A019798 2.3316439815971242033635360621684008763802362991875884230...
%t A019798 RealDigits[Sqrt[2*E], 10, 100][[1]] (* _G. C. Greubel_, Sep 08 2018 *)
%o A019798 (PARI) sqrt(2*exp(1)) \\ _Michel Marcus_, Nov 05 2015
%o A019798 (Magma) SetDefaultRealField(RealField(100)); R:= RealField(); Sqrt(2*Exp(1)); // _G. C. Greubel_, Sep 08 2018
%Y A019798 Cf. A001113, A019774, A257775, A257776.
%K A019798 nonn,cons
%O A019798 1,1
%A A019798 _N. J. A. Sloane_

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