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 A103933 #8 Aug 09 2023 07:06:26 %S A103933 1,4,9,48,150,90,490,2240,11340,2520,152460,83160,2342340,2522520, %T A103933 540540,11531520,104144040,110270160,737176440,775975200,162954792, %U A103933 56904848,1368302936,2141691552,111546435000,116008292400,1084231348200 %N A103933 Denominators of first difference of squares of harmonic numbers A001008/A002805. %C A103933 The corresponding numerators are given in A103932. For the rationals see the link there. %F A103933 a(n)=numerator(r(n)), with the rationals r(n)=H(n)^2-H(n-1)^2 where H(n)= A001008(n)/A002805(n), n>=1, H(0):=0. %t A103933 Denominator[Differences[HarmonicNumber[Range[0,30]]^2]] (* _Harvey P. Dale_, Sep 09 2012 *) %K A103933 nonn,easy,frac %O A103933 1,2 %A A103933 _Wolfdieter Lang_, Mar 24 2005 %E A103933 Offset corrected by _Mohammed Yaseen_, Aug 09 2023