%I #2 Mar 30 2012 18:50:59
%S 1,1,2,3,3,5,5,8,11,11,16,21,21,29,29,40,51,51,67,67,88,109,109,138,
%T 167,167,207,207,258,309,309,376,443,443,531,531,640,749,749,887,887,
%U 1054,1221,1221,1428,1635,1635,1893,1893,2202,2511,2511,2887,2887,3330,3773
%N First differences of A006336.
%C a(n) = A006336(n+1) - A006336(n);
%C a(n+1) - a(n) = A134409(n).
%K nonn
%O 1,3
%A _Reinhard Zumkeller_, Oct 24 2007