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A241794
Number of ballot sequences of length n having exactly one descent.
2
1, 5, 16, 43, 99, 215, 430, 834, 1529, 2765, 4792, 8216, 13684, 22575, 36402, 58285, 91617, 143097, 220317, 337100, 509718, 766655, 1141457, 1690994, 2484138, 3631902, 5271297, 7617750, 10937657, 15640771, 22240250, 31502316, 44396662, 62345539, 87149572
OFFSET
3,2
EXAMPLE
a(3) = 1: [1,2,1].
a(4) = 5: [1,1,2,1], [1,2,1,1], [1,2,1,2], [1,2,1,3], [1,2,3,1].
CROSSREFS
Column k=1 of A238121 and of A238122.
Sequence in context: A143962 A321959 A066634 * A034358 A036888 A053221
KEYWORD
nonn
AUTHOR
Joerg Arndt and Alois P. Heinz, Apr 28 2014
STATUS
approved