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 A194069 #8 Mar 30 2012 18:57:39
%S A194069 1,3,7,11,17,25,33,43,55,67,81,97,113,131,151,171,193,217,241,267,295,
%T A194069 323,353,385,417,451,487,523,561,601,641,683,727,771,817,865,913,963,
%U A194069 1015,1067,1121,1177,1233,1291,1351,1411
%N A194069 1+floor((2/3)*n^2).
%F A194069 a(n)=1+floor(2*n^2/3).
%F A194069 a(n) = 1 +A030511(n+1). - R. J. Mathar, Aug 25 2011
%t A194069 c[k_]:=1+Floor[(2/3)k^2]; c=Table[c[k],{k,1,90}]
%Y A194069 Cf. A194070 (natural fractal sequence),
%Y A194069 A194071 (natural fractal interspersion).
%K A194069 nonn
%O A194069 1,2
%A A194069 _Clark Kimberling_, Aug 14 2011