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 A286478 #14 Dec 19 2021 11:08:18 %S A286478 1,1,2,1,2,1,3,3,4,2,3,1,5,4,5,2,3,1,6,4,5,2,3,1,4,6,7,7,8,6,8,9,10,7, %T A286478 8,4,11,9,10,5,6,2,11,7,8,3,4,1,9,12,13,12,13,9,14,14,15,10,11,5,16, %U A286478 12,13,6,7,2,14,8,9,3,4,1,15,17,18,15,16,10,19,17,18,11,12,5,19,13,14,6,7,2,15,8,9,3,4,1,20,20,21,16,17,10,22,18,19,11,12 %N A286478 Ordinal transform of A034968, factorial base digit sum. %H A286478 Antti Karttunen, <a href="/A286478/b286478.txt">Table of n, a(n) for n = 0..10080</a> %H A286478 <a href="/index/Fa#facbase">Index entries for sequences related to factorial base representation</a> %F A286478 For all n>= 1, a(A000142(n)) = n. %t A286478 f[n_] := If[n == 0, 0, Module[{s = 0, i = 2, k = n}, %t A286478 While[k>0, k = Floor[n/i!]; s += (i-1) k; i++]; n-s]]; %t A286478 b[_] = 1; %t A286478 a[n_] := a[n] = With[{t = f[n]}, b[t]++]; %t A286478 a /@ Range[0, 100] (* _Jean-François Alcover_, Dec 19 2021 *) %Y A286478 Cf. A000142, A034968, A254524 (base-10 analog). %K A286478 nonn,base %O A286478 0,3 %A A286478 _Antti Karttunen_, May 20 2017