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 A068341 #16 Mar 11 2014 01:32:11 %S A068341 1,-2,-1,2,-1,4,-2,0,3,0,-1,-2,1,2,6,-8,0,-2,3,0,5,-4,2,-2,1,-2,1,-6, %T A068341 5,-2,4,-4,5,0,10,-6,-7,-2,2,-4,3,-2,1,-4,-1,4,10,4,4,-14,-1,-4,8,2,2, %U A068341 -12,-3,2,13,10,-11,-10,-2,-6,13,-6,-5,-8,5,2,18,10,-5,-6,-9,0 %N A068341 Sum{k=1 to n} mu(k) mu(n+1-k), where mu(k) is the Moebius function. %H A068341 Reinhard Zumkeller, <a href="/A068341/b068341.txt">Table of n, a(n) for n = 1..10000</a> %t A068341 a[n_] := Sum[ MoebiusMu[k]*MoebiusMu[n + 1 - k], {k, 1, n}]; Table[ a[n], {n, 1, 76}] (* _Jean-François Alcover_, Oct 10 2011 *) %o A068341 (Haskell) %o A068341 a068341 n = a068341_list !! (n-1) %o A068341 a068341_list = f 1 [] where %o A068341 f x ms = (sum $ zipWith (*) ms' $ reverse ms') : f (x + 1) ms' where %o A068341 ms' = (a008683 x) : ms %o A068341 -- _Reinhard Zumkeller_, Aug 03 2012 %K A068341 sign %O A068341 1,2 %A A068341 _Leroy Quet_, Feb 27 2002