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