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

0,6

Comments

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

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

Links

Table of n, a(n) for n=0..50.

Formula

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

Crossrefs

Cf. A000055, A055290, A055277, A262431.

Sequence in context: A192805 A162985 A052523 * A204855 A259098 A367386

Adjacent sequences: A262427 A262428 A262429 * A262431 A262432 A262433

Keyword

nonn

Author

Max Alekseyev, Sep 22 2015

Status

approved