Number of lattice paths from (0,0) to (n,n) using steps (1,0), (1,1), (1,2), and (2,1).

A191354

Number of lattice paths from (0,0) to (n,n) using steps (1,0), (1,1), (1,2), and (2,1).

Terms

    a(0) =1a(1) =1a(2) =3a(3) =9a(4) =25a(5) =75a(6) =227a(7) =693a(8) =2139a(9) =6645a(10) =20757a(11) =65139a(12) =205189a(13) =648427a(14) =2054775a(15) =6526841a(16) =20775357a(17) =66251247a(18) =211617131a(19) =676930325a(20) =2168252571a(21) =6953348149a(22) =22322825865a(23) =71735559255a(24) =230735316795a(25) =742773456825

External references