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 A153789 #15 May 22 2021 05:16:43
%S A153789 5,22,112,130,226,176,966,1332,3230,1928,62,10410,20,9226,2394,2520,
%T A153789 23100,49804,12136,49600,6200,63910,4550,90580,27720,179040,156120,
%U A153789 30660,27300,197496,138294,332010,118440,638820,50960,60760,166740
%N A153789 First differences of harmonic (or Ore) numbers A001599.
%H A153789 Muniru A Asiru, <a href="/A153789/b153789.txt">Table of n, a(n) for n = 1..71</a>
%t A153789 a := Select[Range[1000000], IntegerQ[HarmonicMean[Divisors[#]]] &]; Table[Part[a,n + 1] - Part[a,n], {n,1,30}] (* _G. C. Greubel_, Aug 29 2016 *)
%o A153789 (GAP) H:=Concatenation([1],Filtered([2,4..3*10^6],n->IsInt(n*Tau(n)/Sigma(n))));;
%o A153789 a:=List([1..Length(H)-1],i->H[i+1]-H[i]);; Print(a); # _Muniru A Asiru_, Dec 23 2018
%o A153789 (Python)
%o A153789 from numpy import diff
%o A153789 from sympy import divisor_sigma as sigma
%o A153789 def ore(n): return (n*sigma(n, 0))%sigma(n, 1) == 0
%o A153789 print(diff(list(filter(ore, range(1, 9000))))) # _Michael S. Branicky_, May 22 2021
%Y A153789 Cf. A001599.
%K A153789 nonn
%O A153789 1,1
%A A153789 _Omar E. Pol_, Jan 20 2009
%E A153789 More terms from _R. J. Mathar_, Feb 19 2009