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 A104353 #20 Apr 08 2024 01:41:58
%S A104353 1,3,12,28,168,546,4368,9360,28800,148800,1785600,5401440,75620160,
%T A104353 538793640,2711348640,5603453856,100862169408,303420079872,
%U A104353 6068401597440,30380907997440,213199354368000,2362959510912000,56711028261888000,170288884313856000
%N A104353 Sum of divisors of A104350(n).
%H A104353 Amiram Eldar, <a href="/A104353/b104353.txt">Table of n, a(n) for n = 1..640</a>
%H A104353 Reinhard Zumkeller, <a href="/A104350/a104350.txt">Products of largest prime factors of numbers <= n</a>.
%F A104353 a(n) = A000203(A104350(n)).
%t A104353 DivisorSigma[1, FoldList[Times, Array[FactorInteger[#][[-1, 1]] &, 30]]] (* _Amiram Eldar_, Apr 08 2024 *)
%o A104353 (PARI) gpf(n) = {my(p = factor(n)[, 1]); p[#p];}
%o A104353 a(n) = sigma(prod(k = 2, n, gpf(k))); \\ _Amiram Eldar_, Apr 08 2024
%Y A104353 Cf. A000203, A104350, A104352, A062569.
%K A104353 nonn
%O A104353 1,2
%A A104353 _Reinhard Zumkeller_, Mar 06 2005
%E A104353 a(14), a(21) corrected by _Georg Fischer_, Feb 28 2023