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 A258647 #4 Jun 07 2015 07:29:33 %S A258647 0,0,0,0,4,0,0,0,752,0,0,0,1520,0,0,368,3424,0,0,0,1552,0,0,0,3120,0, %T A258647 176,27,3424,0,0,0,8592,0,0,752,3312,0,0,1520,912,0,0,0,8144,752,0,0, %U A258647 16304,0,368,608,3312,0,5076,1520,8976,0,0,0,8976,0,0,240 %N A258647 Seventh arithmetic derivative of n. %H A258647 Alois P. Heinz, <a href="/A258647/b258647.txt">Table of n, a(n) for n = 0..10000</a> %F A258647 a(n) = A003415^7(n). %p A258647 d:= n-> n*add(i[2]/i[1], i=ifactors(n)[2]): %p A258647 A:= proc(n, k) option remember; `if`(k=0, n, d(A(n, k-1))) end: %p A258647 a:= n-> A(n, 7): %p A258647 seq(a(n), n=0..70); %Y A258647 Column k=7 of A258651. %Y A258647 Cf. A003415. %K A258647 nonn %O A258647 0,5 %A A258647 _Alois P. Heinz_, Jun 06 2015