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), (-1, 1), (0, 1), (1, -1)}.
A151258
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), (-1, 1), (0, 1), (1, -1)}.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =4a(4) =12a(5) =28a(6) =86a(7) =228a(8) =736a(9) =2070a(10) =6868a(11) =20212a(12) =68300a(13) =207620a(14) =711694a(15) =2217096a(16) =7683384a(17) =24405062a(18) =85318256a(19) =275290932a(20) =969323508a(21) =3168559356a(22) =11223800316a(23) =37092325140a(24) =132060026316a(25) =440527174396
External references
- oeis: A151258