A098543 Column 2 of triangle A098542, which shifts left and up under the matrix square.

1, 4, 12, 44, 236, 2028, 29164, 719340, 30943724, 2350770668, 318680099308, 77793540073964, 34472347123476972, 27928291976711924204, 41631598900551078537708, 114829789064202679162399212

Offset

2,2

Comments

Related to A002449, the number of different types of binary trees of height n.

Links

Table of n, a(n) for n=2..17.

Formula

G.f.: A(x) = x*(1+x)/(1-x)*(G002449(x)-1), where G002449(x) is g.f. of A002449.

Crossrefs

Cf. A002449, A098542, A098544.

Sequence in context: A226855 A039740 A065143 * A028407 A105344 A074035

Adjacent sequences: A098540 A098541 A098542 * A098544 A098545 A098546

Keyword

nonn

Author

Paul D. Hanna, Sep 16 2004

Status

approved