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 A181171 #13 Apr 19 2014 01:42:32 %S A181171 1,6,3,6,6,2,6,2,0,7,7,8,0,9,2,3,7,7,0,6,6,3,9,2,3,4,8,9,7,2,1,8,3,5, %T A181171 0,2,1,8,2,4,4,1,7,1,6,0,2,9,9,4,1,7,0,8,6,8,5,8,7,4,2,6,0,0,5,8,9,0, %U A181171 2,0,9,6,4,6,0,3,9,5,8,5,9,7,3,6,5,1,9,7,1,8,1,0,6,0,0,8,7,6,2,0,3,9,1,5,0 %N A181171 Decimal expansion of the base x for which the double logarithm of 2 equals the natural log of 2, that is, log_x log_x 2 = log 2. %e A181171 From _R. J. Mathar_, Oct 09 2010: (Start) %e A181171 1.63662620778092377066392348972183502182... %e A181171 log_(1.63662..)(2) = 1.4070142427036... %e A181171 log_(1.63662..)(1.407014..) = A002162. (End) %p A181171 f := log(log(2))/log(x)-log(log(x))/log(x)-log(2) ; fz := x-f/diff(f,x) ; z := 1.6 ; Digits := 120 ; for i from 1 to 10 do z := evalf(subs(x=z,fz)) ; print(%) ; end do: # _R. J. Mathar_, Oct 09 2010 %t A181171 RealDigits[ Exp[ ProductLog[Log[2]^2] / Log[2]], 10, 105][[1]] (* _Jean-François Alcover_, Jan 28 2014 *) %Y A181171 Cf. A030797, which is the decimal expansion of the base n for which the double logarithm of e (log_n log_n e) = log e = 1, and which is the inverse of LambertW(1). %K A181171 nonn,cons %O A181171 1,2 %A A181171 _Geoffrey Caveney_, Oct 08 2010 %E A181171 More digits from _R. J. Mathar_, Oct 09 2010