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Partial sums of A000014.
0

%I #6 Sep 14 2021 05:30:42

%S 0,1,2,2,3,4,6,8,12,17,27,41,67,109,187,319,568,1013,1855,3416,6404,

%T 12075,23056,44265,85737,166918,327094,643843,1273776,2529846,5045015,

%U 10094831,20267469,40811048,82413473,166854359,338648851,688887026,1404384063,2868791176,5871429462,12038444069

%N Partial sums of A000014.

%C Number of series-reduced trees with <= n nodes.

%F a(n) = Sum_{k=0..n} A000014(k).

%Y Cf. A000014, A000055 (trees), A001678 (series-reduced planted trees), A007827 (series-reduced trees by leaves).

%K easy,nonn

%O 0,3

%A _Jonathan Vos Post_, Feb 17 2010

%E a(3)=2 inserted and edited by _Georg Fischer_, Sep 14 2021