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 A247864 #16 Feb 16 2025 08:33:23 %S A247864 2,1,0,1,8,9,3,9,4,5,3,3,5,2,0,4,1,8,9,0,5,2,7,9,7,1,8,5,6,8,8,0,8,4, %T A247864 9,0,1,9,9,5,9,9,2,0,0,7,4,5,8,4,2,3,9,0,6,5,8,8,0,0,3,7,2,9,5,5,2,9, %U A247864 7,8,9,5,7,2,2,8,3,4,5,6,7,8,0,5,4,6,0,8,0,2,2,5,4,4,3,2,4,0,3 %N A247864 Decimal expansion of c = 1/(2^(e^(-gamma))-1), a constant associated with the asymptotic convergent denominators of a continued fraction using Mersenne primes. %H A247864 G. C. Greubel, <a href="/A247864/b247864.txt">Table of n, a(n) for n = 1..10000</a> %H A247864 Eric Weisstein's MathWorld, <a href="https://mathworld.wolfram.com/MersennePrime.html">Mersenne Prime</a> %H A247864 Marek Wolf, <a href="http://arxiv.org/abs/1003.4015">"Continued fractions constructed from prime numbers"</a> arXiv:1003.4015 [math.NT] Sep 26 2010, p. 24. %F A247864 c = 1/(2^(e^(-gamma))-1), where gamma is Euler's constant 0.5772... %e A247864 2.1018939453352041890527971856880849019959920074584239... %t A247864 c = 1/(2^(E^(-EulerGamma)) - 1); RealDigits[c, 10, 99] // First %o A247864 (PARI) 1/(2^(exp(-Euler))-1) \\ _Michel Marcus_, Sep 25 2014 %o A247864 (Magma) SetDefaultRealField(RealField(100)); R:= RealField(); 1/(2^(Exp(-EulerGamma(R))) - 1); // _G. C. Greubel_, Sep 04 2018 %Y A247864 Cf. A000668, A001620. %K A247864 nonn,cons,easy %O A247864 1,1 %A A247864 _Jean-François Alcover_, Sep 25 2014