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 A104351 #10 Apr 08 2024 06:54:27
%S A104351 1,1,1,2,2,3,4,4,4,5,6,7,8,9,9,10,11,11,13,13,14,15,16,17,18,19,19,20,
%T A104351 22,22,24,24,25,26,27,28,29,30,32,32,34,35,36,37,38,40,41,42,42,43,44,
%U A104351 46,47,48,49,50,51,52,54,55,57,58,59,59,60,61,63,64,66,67,69,69,71,72
%N A104351 Number of digits in decimal representation of A104350(n).
%H A104351 Amiram Eldar, <a href="/A104351/b104351.txt">Table of n, a(n) for n = 1..10000</a>
%H A104351 Reinhard Zumkeller, <a href="/A104350/a104350.txt">Products of largest prime factors of numbers <= n</a>.
%F A104351 a(n) = A055642(A104350(n)).
%t A104351 IntegerLength[FoldList[Times, Array[FactorInteger[#][[-1, 1]] &, 100]]] (* _Amiram Eldar_, Apr 08 2024 *)
%o A104351 (PARI) gpf(n) = {my(p = factor(n)[, 1]); p[#p];}
%o A104351 a(n) = logint(prod(k = 2, n, gpf(k)), 10) + 1; \\ _Amiram Eldar_, Apr 08 2024
%Y A104351 Cf. A034886, A055642, A104350.
%K A104351 nonn,base
%O A104351 1,4
%A A104351 _Reinhard Zumkeller_, Mar 06 2005