|
Search: id:A151357
|
|
|
| A151357 |
|
Number of walks within N^2 (the first quadrant of Z^2) starting and ending at (0,0) and consisting of n steps taken from {(-1, -1), (-1, 0), (0, 1), (1, -1), (1, 0)} |
|
+0
1
|
|
| 1, 0, 1, 3, 4, 20, 65, 175, 742, 2604, 9072, 36960, 139392, 538824, 2198625, 8735727, 35456850, 146812952, 604215326, 2521642266, 10617725768, 44760668160, 190357768328, 813800295880, 3490232753680, 15055389124320, 65193213272800, 283254330047520, 1235731377864960, 5407996483238160
(list; graph; listen)
|
|
|
OFFSET
|
0,4
|
|
|
LINKS
|
M. Bouquet-Melou and M. Mishna, 2008. Walks with small steps in the quarter plane, ArXiv 0810.4387.
|
|
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, j, -1 + n] + aux[-1 + i, 1 + j, -1 + n] + aux[i, -1 + j, -1 + n] + aux[1 + i, j, -1 + n] + aux[1 + i, 1 + j, -1 + n]]; Table[aux[0, 0, n], {n, 0, 25}]
|
|
CROSSREFS
|
Sequence in context: A062870 A151419 A067281 this_sequence A009169 A069934 A032830
Adjacent sequences: A151354 A151355 A151356 this_sequence A151358 A151359 A151360
|
|
KEYWORD
|
nonn,walk
|
|
AUTHOR
|
Manuel Kauers (manuel(AT)kauers.de), Nov 18 2008
|
|
|
Search completed in 0.002 seconds
|
