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 A231095 #28 Oct 26 2014 17:54:15 %S A231095 6,8,5,9,4,7,0,3,5,1,6,7,4,2,8,4,8,1,8,7,5,7,3,5,9,6,1,9,8,0,4,1,7,3, %T A231095 5,8,7,4,8,8,6,2,1,4,1,8,7,0,3,0,1,5,0,6,7,0,1,8,6,6,8,5,8,1,7,0,3,0, %U A231095 1,8,7,6,7,1,4,6,9,5,7,3,8,5,6,1,7,8,3,7,3,7,0,1,6,5,9,1,1,1,0,4,8,9,1,5,0 %N A231095 Decimal expansion of the power tower of Euler constant gamma. %H A231095 Stanislav Sykora, <a href="/A231095/b231095.txt">Table of n, a(n) for n = 0..2000</a> %H A231095 Wikipedia, <a href="http://en.wikipedia.org/wiki/Euler_constant">Euler-Mascheroni constant</a> %H A231095 Wikipedia, <a href="http://en.wikipedia.org/wiki/Lambert_W_function">Lambert W function</a> %H A231095 Wikipedia, <a href="http://en.wikipedia.org/wiki/Tetration">Tetration</a> %F A231095 In general, for 1/E^E <= c < 1, c^c^c^... = LambertW(log(1/c))/log(1/c). Hence, this number is LambertW(log(1/gamma))/log(1/gamma). %e A231095 0.685947035167428481875735 ... %p A231095 evalf(-LambertW(-log(gamma))/log(gamma), 120); # _Vaclav Kotesovec_, Oct 26 2014 %t A231095 c = EulerGamma; RealDigits[ ProductLog[-Log[c]]/Log[c], 10, 111] (* _Robert G. Wilson v_, Oct 24 2014 *) %o A231095 (PARI) -lambertw(-log(Euler))/log(Euler) %Y A231095 Cf. A001620. %K A231095 nonn,cons %O A231095 0,1 %A A231095 _Stanislav Sykora_, Nov 03 2013