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), (0, -1), (0, 1), (1, 1)}.
A151290
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), (0, -1), (0, 1), (1, 1)}.
Terms
- a(0) =1a(1) =2a(2) =7a(3) =23a(4) =82a(5) =297a(6) =1092a(7) =4074a(8) =15316a(9) =57993a(10) =220913a(11) =845017a(12) =3245513a(13) =12504416a(14) =48308973a(15) =187089688a(16) =726028123a(17) =2822654120a(18) =10991682069a(19) =42864045010a(20) =167373921420a(21) =654315764945
External references
- oeis: A151290