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A249385 Decimal expansion of gamma - 2*Ei(-1), one of the Tauberian constants, where Ei is the exponential integral function.

%I A249385 #20 Feb 16 2025 08:33:24
%S A249385 1,0,1,5,9,8,3,5,3,3,6,9,2,5,7,3,4,0,7,9,6,0,8,3,9,6,4,1,0,0,2,6,4,5,
%T A249385 7,2,9,1,0,4,2,5,3,9,2,2,7,5,3,7,4,0,0,1,3,9,6,1,7,2,4,4,6,1,0,3,2,0,
%U A249385 0,5,1,2,3,8,9,5,9,4,7,7,6,0,3,8,1,3,6,7,5,6,5,3,6,2,0,2,1,2,4,9,4,2,4
%N A249385 Decimal expansion of gamma - 2*Ei(-1), one of the Tauberian constants, where Ei is the exponential integral function.
%H A249385 G. C. Greubel, <a href="/A249385/b249385.txt">Table of n, a(n) for n = 1..10000</a>
%H A249385 Steven R. Finch, <a href="/A202501/a202501.pdf">Tauberian Constants</a>, August 30, 2004 [Cached copy, with permission of the author]
%H A249385 Eric Weisstein's MathWorld, <a href="https://mathworld.wolfram.com/ExponentialIntegral.html">Exponential Integral</a>
%F A249385 Also equals gamma + 2*G/e, where G is the Euler-Gompertz constant 0.596347...
%F A249385 Equals A001620 + 2*A073003/e. - _G. C. Greubel_, Sep 04 2018
%e A249385 1.01598353369257340796083964100264572910425392275374...
%p A249385 evalf(gamma - 2*Ei(-1), 120); # _Vaclav Kotesovec_, Oct 27 2014
%t A249385 RealDigits[ EulerGamma - 2*ExpIntegralEi[-1], 10, 103] // First
%o A249385 (PARI) default(realprecision, 100); Euler + 2*eint1(1) \\ _G. C. Greubel_, Sep 04 2018
%Y A249385 Cf. A001620, A073003, A099285, A248472.
%K A249385 nonn,cons,easy
%O A249385 1,4
%A A249385 _Jean-François Alcover_, Oct 27 2014