A241794 Number of ballot sequences of length n having exactly one descent.

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

Links

Table of n, a(n) for n=3..37.

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

Adjacent sequences: A241791 A241792 A241793 * A241795 A241796 A241797

Keyword

nonn

Author

Joerg Arndt and Alois P. Heinz, Apr 28 2014

Status

approved