A288541 Number of Dyck paths of semilength n such that the minimal number of peaks over all positive levels equals two.

1, 0, 0, 3, 13, 30, 61, 172, 619, 2241, 7736, 25786, 85315, 286653, 986444, 3465777, 12342188, 44275218, 159463056, 576136367, 2089063623, 7607265038, 27829092314, 102263653872, 377340952123, 1397457667346, 5192248524833, 19348310336881, 72292940817636

Offset

2,4

Links

Alois P. Heinz, Table of n, a(n) for n = 2..300

Wikipedia, Counting lattice paths

Example

: a(5) = 3:
:
:            /\/\      /\/\      /\/\
:       /\/\/    \  /\/    \/\  /    \/\/\  .

Crossrefs

Column k=2 of A288387.

Cf. A000108.

Sequence in context: A352267 A330451 A022264 * A296014 A273337 A273769

Adjacent sequences: A288538 A288539 A288540 * A288542 A288543 A288544

Keyword

nonn

Author

Alois P. Heinz, Jun 11 2017

Status

approved