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 A085393 #11 Dec 04 2017 08:59:09
%S A085393 0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,3,0,0,0,1,0,0,0,5,0,2,0,0,0,0,
%T A085393 0,1,0,0,0,3,0,4,0,9,2,0,0,1,0,0,0,11,0,0,0,5,0,0,0,3,0,0,4,0,0,8,0,
%U A085393 15,0,2,0,1,0,0,0,17,0,10,0,3,0,0,0,5,0,0,0,9,0,2,0,21,0,0,0,1,0,0,8,3,0,14
%N A085393 Difference between the largest and the smallest prime factor of the greatest proper divisor of n.
%H A085393 Antti Karttunen, <a href="/A085393/b085393.txt">Table of n, a(n) for n = 1..16384</a>
%F A085393 a(n) = A085392(n) - A014673(n).
%t A085393 PrimeFactors[n_] := Flatten[ Table[ # [[1]], {1}] & /@ FactorInteger[n]]; f[n_] := Block[{gpd = Divisors[n][[ -2]]}, If[gpd == 1, 0, PrimeFactors[gpd][[ -1]] - PrimeFactors[gpd][[1]] ]]; Table[ If[n == 1, 0, f[n]], {n, 1, 102}]
%t A085393 {1}~Join~Array[#[[-1, 1]] - #[[1, 1]] &@ FactorInteger@ Last@ Most@ Divisors@ # &, 101, 2] (* _Michael De Vlieger_, Dec 03 2017 *)
%Y A085393 Cf. A014673, A085392.
%K A085393 nonn
%O A085393 1,20
%A A085393 _Robert G. Wilson v_ and _Reinhard Zumkeller_, Jun 26 2003