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 A255409 #14 Mar 04 2024 01:38:19
%S A255409 0,1,4,18,24,27,160,1470,1500,1701,1920,2205,25515,27951,392392,
%T A255409 424710,429000,481250,500500,8824530,8825856,185435250,194922000,
%U A255409 204289085,214451328
%N A255409 a(n) = the least k for which A255326(k) = n; positions of records in A255326.
%C A255409 Upper bounds of a(25), ..., a(39) are 5144855625, 5167255808, 5418041805, 5449966080, 6041677950, 187630152192, 187692817422, 188598924800, 195087679875, 6235115927040, 6235116982094, 6827777110000, 7028593647075, 7229398816640, 7251520647683, respectively. - _Hiroaki Yamanouchi_, Mar 30 2015
%F A255409 Other identities:
%F A255409 For all n >= 0, A255326(a(n)) = n.
%t A255409 f[0] = 0; f[n_] := f[n] = 1 + f[n - Times @@ FactorInteger[n][[;; , 1]]]; seq[nmax_] := Module[{s = {}, f1, fm = -1}, Do[f1 = f[n]; If[f1 > fm, fm = f1; AppendTo[s, n]], {n, 0, nmax}]; s]; seq[510000] (* _Amiram Eldar_, Mar 04 2024 *)
%o A255409 (Scheme, with _Antti Karttunen_'s IntSeq-library)
%o A255409 (define A255409 (RECORD-POS 0 0 A255326))
%Y A255409 Cf. A255326.
%K A255409 nonn,more
%O A255409 0,3
%A A255409 _Antti Karttunen_, Mar 23 2015
%E A255409 a(14)-a(24) from _Hiroaki Yamanouchi_, Mar 30 2015