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 A105856 #3 Mar 30 2012 18:50:49 %S A105856 0,1,2,4,7,12,20,26,32,44,52,61,78,91,107,121,135,163,187,201,219,251, %T A105856 279,293,311,343,367,396,421,446,496,540,570,611,648,656,665,682,708, %U A105856 751,780,811,871,919,939,962,1005,1071,1132,1161,1201,1270,1327,1347 %N A105856 a(n) = a(n-1) + A104647(n), a(0) = 0. %C A105856 a(n)/(n^2) ---> 1/2. %K A105856 nonn %O A105856 0,3 %A A105856 _Reinhard Zumkeller_, Apr 23 2005