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 A095774 #8 Aug 02 2013 23:08:26 %S A095774 1,0,-1,0,1,2,1,0,1,0,-1,0,-1,-2,-1,0,1,0,-1,0,1,2,1,0,1,2,3,2,1,2,1, %T A095774 0,1,0,-1,0,1,2,1,0,1,0,-1,0,-1,-2,-1,0,1,0,-1,0,-1,-2,-1,-2,-3,-2,-1, %U A095774 0,-1,-2,-1,0,1,0,-1,0,1,2,1,0,1,0,-1,0,-1,-2,-1,0,1,0,-1,0,1,2,1,0,1,2,3,2,1,2,1,0,1,0,-1,0,1,2,1,0,1,2,3,2,1,2,3,4,3,2 %N A095774 a(n)=2*A003160(n)-n. %H A095774 Reinhard Zumkeller, <a href="/A095774/b095774.txt">Table of n, a(n) for n = 1..10000</a> %o A095774 (PARI) m=1106;v=vector(m,j,1);for(n=3,m,g=n-v[v[n-1]]-v[v[n-2]];v[n]=g);a(n)=2*v[n]-n %o A095774 (Haskell) %o A095774 a095774 n = 2 * a003160 n - n -- _Reinhard Zumkeller_, Aug 02 2013 %K A095774 sign %O A095774 1,6 %A A095774 _Benoit Cloitre_, Jun 05 2004 %E A095774 Offset corrected by _Reinhard Zumkeller_, Aug 02 2013