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A107652
Triangle of numbers arising in enumeration of binary trees.
3
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
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
KEYWORD
nonn,tabl,easy
STATUS
approved