Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0) and consisting of n steps taken from {(-1, 1), (0, 1), (1, -1), (1, 0)}.
A151284
Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0) and consisting of n steps taken from {(-1, 1), (0, 1), (1, -1), (1, 0)}.
Terms
- a(0) =1a(1) =2a(2) =6a(3) =20a(4) =70a(5) =254a(6) =942a(7) =3550a(8) =13532a(9) =52030a(10) =201386a(11) =783560a(12) =3061442a(13) =12001804a(14) =47181278a(15) =185904220a(16) =733908634a(17) =2901998092a(18) =11490757796a(19) =45552262860a(20) =180762964146a(21) =717939220774
External references
- oeis: A151284