|
| |
|
|
A151293
|
|
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), (1, -1), (1, 1)}
|
|
0
| |
|
|
1, 2, 7, 24, 88, 328, 1246, 4779, 18485, 71918, 281102, 1102653, 4337842, 17104951, 67577658, 267410057, 1059581561, 4203221319, 16689714274, 66324649355, 263761185264, 1049579758069, 4178825351781, 16645543692333, 66331807758634, 264426232745902, 1054454512710944, 4206064951123326
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,2
|
|
|
LINKS
| M. Bousquet-Melou and M. Mishna, 2008. Walks with small steps in the quarter plane, ArXiv 0810.4387.
A. Bostan and M. Kauers, 2008. Automatic Classification of Restricted Lattice Walks, ArXiv 0811.2899.
|
|
|
MATHEMATICA
| aux[i_Integer, j_Integer, n_Integer] := Which[Min[i, j, n] < 0 || Max[i, j] > n, 0, n == 0, KroneckerDelta[i, j, n], True, aux[i, j, n] = aux[-1 + i, -1 + j, -1 + n] + aux[-1 + i, 1 + j, -1 + n] + aux[i, -1 + j, -1 + n] + aux[1 + i, j, -1 + n]]; Table[Sum[aux[i, j, n], {i, 0, n}, {j, 0, n}], {n, 0, 25}]
|
|
|
CROSSREFS
| Sequence in context: A150389 A183876 A104625 * A122446 A150390 A052705
Adjacent sequences: A151290 A151291 A151292 * A151294 A151295 A151296
|
|
|
KEYWORD
| nonn,walk
|
|
|
AUTHOR
| Manuel Kauers (manuel(AT)kauers.de), Nov 18 2008
|
| |
|
|
