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 A234715 #7 Dec 31 2013 02:56:24
%S A234715 1,1,3,33,825,113025,5538225,60920475,46360481475,330503872435275,
%T A234715 20160736218551775,1687675389591187637025,145175524688023551724527525,
%U A234715 166370135063802174111446471957325,194941377468714112878127508925972294225,8038017817167489016303831575544615607779425
%N A234715 Denominator of sum_{k=1..n} 1/(k*H(k)) where H(k) is the harmonic number H(k) = sum_{j=1..n} 1/j.
%C A234715 The corresponding numerators are in A234714.
%C A234715 A124432(n) = a(n) for 0 <= n <= 53, but A124432(54) = 3 * a(54).
%t A234715 nmax = 54; Table[ Denominator[ Sum[ 1/(k HarmonicNumber[k]), {k, 1, n} ] ], {n, 0, nmax} ]
%Y A234715 Cf. A001008, A002805, A000254, A096987, A124432, A234714
%K A234715 nonn,easy
%O A234715 0,3
%A A234715 _Stuart Clary_, Dec 29 2013