Number of walks on cubic lattice starting and finishing on the xy plane and never going below it.

A005572

Number of walks on cubic lattice starting and finishing on the xy plane and never going below it.

Terms

    a(0) =1a(1) =4a(2) =17a(3) =76a(4) =354a(5) =1704a(6) =8421a(7) =42508a(8) =218318a(9) =1137400a(10) =5996938a(11) =31940792a(12) =171605956a(13) =928931280a(14) =5061593709a(15) =27739833228a(16) =152809506582a(17) =845646470616

External references