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 A258863 #8 Aug 31 2015 21:19:55 %S A258863 0,1,1,2,-1,4,-3,8,0,-1,-6,15,-14,9,4,13,-25,26,-25,24,-6,-5,-12,43, %T A258863 -22,-5,29,-10,-34,43,-42,69,-43,-6,10,43,-72,23,9,40,-71,60,-59,50, %U A258863 23,-46,-26,113,-72,29,-30,21,-60,119,-77,58,-54,-13,-32,119,-118 %N A258863 First differences of the pi-based arithmetic derivative sequence A258851. %H A258863 Alois P. Heinz, <a href="/A258863/b258863.txt">Table of n, a(n) for n = 0..10000</a> %F A258863 a(n) = A258851(n+1) - A258851(n). %p A258863 with(numtheory): %p A258863 d:= n-> n*add(i[2]*pi(i[1])/i[1], i=ifactors(n)[2]): %p A258863 a:= n-> d(n+1)-d(n): %p A258863 seq(a(n), n=0..100); %Y A258863 Cf. A000720, A258851. %K A258863 sign,look %O A258863 0,4 %A A258863 _Alois P. Heinz_, Jun 12 2015