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 A206475 #15 Apr 15 2018 21:57:48 %S A206475 0,1,1,1,-2,4,-1,2,-3,6,-4,6,-6,2,3,5,-9,11,-6,0,-2,12,-12,11,-9,8,-2, %T A206475 10,-20,22,-9,-1,-4,8,-3,15,-18,6,-4,20,-28,30,-12,-2,-6,24,-24,21, %U A206475 -22,11,4,16,-32,20,-10,6,-8,30,-34,36,-30,12,1,5,-28,46 %N A206475 First differences of A206369. %C A206475 a(A206368(n)) = 0. %H A206475 Reinhard Zumkeller, <a href="/A206475/b206475.txt">Table of n, a(n) for n = 1..10000</a> %F A206475 a(n) = A206369(n+1) - A206369(n). %t A206475 (* b = A206369 *) b[n_] := n*DivisorSum[n, LiouvilleLambda[#]/# &]; %t A206475 Array[b, 100] // Differences (* _Jean-François Alcover_, Dec 04 2017 *) %o A206475 (Haskell) %o A206475 a206475 n = a206475_list !! (n-1) %o A206475 a206475_list = zipWith (-) (tail a206369_list) a206369_list %K A206475 sign %O A206475 1,5 %A A206475 _Reinhard Zumkeller_, Feb 08 2012