Number of log-concave paths of length n starting from the origin (0,0) with steps from {N=(0,1), E=(1,0) and S=(0,-1)} that stay in the second octant and never touch the line y=x except possibly at the beginning or the end.

A079280

Number of log-concave paths of length n starting from the origin (0,0) with steps from {N=(0,1), E=(1,0) and S=(0,-1)} that stay in the second octant and never touch the line y=x except possibly at the beginning or the end.

Terms

    a(0) =1a(1) =2a(2) =2a(3) =5a(4) =7a(5) =17a(6) =26a(7) =62a(8) =99a(9) =233a(10) =382a(11) =890a(12) =1486a(13) =3434a(14) =5812a(15) =13340a(16) =22819a(17) =52073a(18) =89846a(19) =204002a(20) =354522a(21) =801422a(22) =1401292a(23) =3155300a(24) =5546382a(25) =12444842a(26) =21977516a(27) =49155332a(28) =87167164a(29) =194392628

External references