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 A081805 #19 Aug 26 2018 11:34:13
%S A081805 0,0,0,0,0,3,0,0,0,5,0,8,0,7,10,0,0,9,0,15,14,11,0,16,0,13,0,21,0,25,
%T A081805 0,0,22,17,28,27,0,19,26,32,0,35,0,33,36,23,0,32,0,25,34,39,0,27,44,
%U A081805 48,38,29,0,55,0,31,54,0,52,55,0,51,46,63,0,63,0,37,50,57,66,65,0,64,0,41,0
%N A081805 a(n) = n minus (largest prime power in n factorization); a(1) = 0.
%C A081805 a(n) = 0 when n is a prime power (A000961). - _Michel Marcus_, Dec 03 2013
%H A081805 Antti Karttunen, <a href="/A081805/b081805.txt">Table of n, a(n) for n = 1..65537</a>
%F A081805 a(n) = n - A034699(n). - _Michel Marcus_, Jul 24 2017
%t A081805 f[n_] := (n - (#[[1]]^#[[2]]) & /@ {FactorInteger[n][[-1]] })[[1]]; Array[f, 80] (* _Robert G. Wilson v_, Aug 07 2018 *)
%o A081805 (PARI) A081805(n) = if(1==n,0,my(f = factor(n)); n - vecmax(vector(#f~, k, f[k, 1]^f[k, 2]))); \\ _Michel Marcus_ Jul 24 2017 & _Antti Karttunen_, Aug 06 2018
%Y A081805 Cf. A034699, A052128, A284600.
%K A081805 nonn
%O A081805 1,6
%A A081805 _Benoit Cloitre_, Apr 10 2003
%E A081805 Term a(1) = 0 prepended by _Antti Karttunen_, Aug 06 2018