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 A203234 #7 Oct 15 2013 14:13:14 %S A203234 1,2,3,7,9,11,13,28,32,36,40,84,92,100,108,224,240,256,272,560,592, %T A203234 624,656,1344,1408,1472,1536,3136,3264,3392,3520,7168,7424,7680,7936, %U A203234 16128,16640,17152,17664,35840,36864,37888,38912,78848,80896 %N A203234 (n-1)-st elementary symmetric function of the first n terms of the periodic sequence (1,1,1,2,1,1,1,2,...). %F A203234 Conjecture: a(n) = 4*a(n-4)-4*a(n-8) with G.f. x*(1+2*x+3*x^2+7*x^3+5*x^4+3*x^5+x^6) / (-1+2*x^4)^2 . - _R. J. Mathar_, Oct 15 2013 %t A203234 r = {1, 1, 1, 2, 1, 1, 1, 2}; %t A203234 s = Flatten[{r, r, r, r, r, r, r, r, r}]; %t A203234 t[n_] := Part[s, Range[n]] %t A203234 a[n_] := SymmetricPolynomial[n - 1, t[n]] %t A203234 Table[a[n], {n, 1, 45}] (* A203234 *) %Y A203234 Cf. A203235. %K A203234 nonn %O A203234 1,2 %A A203234 _Clark Kimberling_, Dec 30 2011