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 A091950 #6 Mar 30 2012 18:39:22 %S A091950 1,0,0,2,1,1,2,1,1,1,0,0,2,1,1,2,2,2,1,0,0,2,1,1,0,0,0,1,0,0,2,1,1,2, %T A091950 1,1,1,0,0,2,1,1,2,2,2,1,0,0,2,1,1,0,1,1,1,0,0,2,1,1,2,1,1,1,0,0,2,1, %U A091950 1,2,2,2,1,0,0,2,1,1,2,1,1,1,0,0,2,1,1,2,1,1,1,0,0,2,1,1,2,2,2,1,0,0,2,1,1 %N A091950 a(n) = A087659(n) mod 3. %F A091950 a(n)=hypergeom([ -n, (n+4)/2, (n+5)/2], [3, 2], -4) mod 3; a(9k)=1, a(9k+1)=0, a(9k+2)=0, a(9k+3)=2, a(9k+4)=1, a(9k+5)=1, a(9k+6)=2*A014578(k+1), a(9k+7)=z(k), a(9k+8)=z(k) where : z(9k)=1, z(9k+1)=2, z(9k+2)=0, z(9k+3)=1, z(9k+4)=2, z(9k+5)=1, z(9k+6)=1, z(9k+7)=2 and z(9k+8)=z(k). %o A091950 (PARI) a(n)= sum(i=0,n,2*binomial(n,i)*(n+2*i+3)!/((i+1)!*(i+2)!*(n+3)!))%3 %K A091950 nonn %O A091950 0,4 %A A091950 _Benoit Cloitre_, Mar 11 2004