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 A103930 #20 Aug 30 2019 03:36:19 %S A103930 1,9,121,625,18769,2401,131769,579121,50822641,54479161,7007531521, %T A103930 7399612441,1313299956049,1372958223289,1429834803049,5936819760481, %U A103930 1775966959381729,203755669038601,75787776947048401,3117562300468225 %N A103930 Numerators of squares of harmonic numbers A001008/A002805. %C A103930 The corresponding denominators are given in A103931. %H A103930 W. Lang: <a href="/A103930/a103930.txt">Rationals H(n)^2.</a> %F A103930 G.f.: -((d^3/dx^3)((log(1-x))^3))/3 + dilog(1-x)/(1-x) = ((log(1-x)^2) + dilog(1-x))/(1-x) with dilog(1-x)=polylog(2, x). %F A103930 First differences give A103932(n)/A103933(n). %F A103930 a(n) = numerator(H(n)^2), with the harmonic numbers H(n) = A001008(n)/A002805(n), n >= 1. %p A103930 A103930 := n->numer(sum(1/i, i=1..n)^2); seq(A103930(k), k=1..40); # _Wesley Ivan Hurt_, Sep 30 2013 %t A103930 a[n_] := HarmonicNumber[n]^2 // Numerator; Table[a[n], {n, 1, 20}] (* _Jean-François Alcover_, Sep 16 2013 *) %K A103930 nonn,easy,frac %O A103930 1,2 %A A103930 _Wolfdieter Lang_, Mar 24 2005