Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0) and consisting of n steps taken from {(-1, 0), (1, -1), (1, 1)}.
A151266
Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0) and consisting of n steps taken from {(-1, 0), (1, -1), (1, 1)}.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =7a(4) =19a(5) =49a(6) =139a(7) =379a(8) =1079a(9) =3011a(10) =8681a(11) =24641a(12) =71303a(13) =204359a(14) =594749a(15) =1717871a(16) =5012591a(17) =14552407a(18) =42601285a(19) =124209955a(20) =364300377a(21) =1065449397a(22) =3131483367a(23) =9182889013a(24) =27027421303a(25) =79418096239a(26) =234090990589a(27) =689093244919
External references
- oeis: A151266