A262430 Number of trees on n vertices with an even number of leaves.

1, 0, 1, 1, 1, 2, 3, 6, 12, 25, 54, 120, 278, 657, 1586, 3885, 9676, 24350, 61974, 159066, 411637, 1072477, 2812147, 7414611, 19650656, 52319946, 139898593, 375536661, 1011726481, 2734793731, 7415449225, 20165442393, 54986240994, 150314506170, 411889913114, 1131183374539, 3113153283443, 8584839296108, 23718157486109, 65645273392938, 181995130879151, 505374042479921, 1405493247220915, 3914493122094481, 10917513971606377, 30489195524251154, 85254349619909519, 238677545463592954, 668973050139380099, 1877097093098685409, 5272616851780131627

Offset: 0

Author

Max Alekseyev, Sep 22 2015

Keywords

• nonn

Comments

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

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

Crossrefs

Cf. A000055, A055290, A055277, A262431.

Formula

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