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Number of trees on n vertices with an even number of leaves.
2

%I #7 Sep 22 2015 13:28:29

%S 1,0,1,1,1,2,3,6,12,25,54,120,278,657,1586,3885,9676,24350,61974,

%T 159066,411637,1072477,2812147,7414611,19650656,52319946,139898593,

%U 375536661,1011726481,2734793731,7415449225,20165442393,54986240994,150314506170,411889913114,1131183374539,3113153283443,8584839296108,23718157486109,65645273392938,181995130879151,505374042479921,1405493247220915,3914493122094481,10917513971606377,30489195524251154,85254349619909519,238677545463592954,668973050139380099,1877097093098685409,5272616851780131627

%N Number of trees on n vertices with an even number of leaves.

%C For n>=0, a(n) + A262431(n) = A000055(n).

%C For n>=2, a(n) - A262431(n) = A262395(n).

%F G.f.: (A(x,1)+A(x,-1))/2, where A(x,y) is g.f. for A055290.

%Y Cf. A000055, A055290, A055277, A262431.

%K nonn

%O 0,6

%A _Max Alekseyev_, Sep 22 2015