A107652 Triangle of numbers arising in enumeration of binary trees.

1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 4, 8, 10, 8, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 34, 68, 94, 104, 94, 68, 34, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 496, 992, 1420, 1712, 1816, 1712, 1420, 992, 496, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Offset

0,13

Comments

Essentially the same triangle as in A008301, but with more zeros.

Links

Table of n, a(n) for n=0..78.

Christiane Poupard, Deux propriétés des arbres binaires ordonnés stricts, Europ. J. Combin., Vol. 10 (1989), pp. 369-374.

Crossrefs

Cf. A008301. Leading diagonal and row sums = (essentially) A107652.

Sequence in context: A356996 A037860 A037878 * A186734 A196096 A249344

Adjacent sequences: A107649 A107650 A107651 * A107653 A107654 A107655

Keyword

nonn,tabl,easy

Author

N. J. A. Sloane

Status

approved