|
| |
|
|
A149930
|
|
Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 0, 1), (0, 1, 0), (1, -1, -1), (1, 0, 0)}
|
|
0
|
|
|
|
1, 2, 5, 15, 48, 171, 637, 2428, 9550, 38349, 156705, 650514, 2730685, 11586035, 49633476, 214245357, 931290307, 4073517547, 17914555800, 79177186936, 351493613879, 1566615341461, 7008105335834, 31454517640160, 141606919092096, 639300738693485, 2893656057013955, 13128807209968934
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
0,2
|
|
|
LINKS
|
Table of n, a(n) for n=0..27.
A. Bostan and M. Kauers, 2008. Automatic Classification of Restricted Lattice Walks, ArXiv 0811.2899.
|
|
|
MATHEMATICA
|
aux[i_Integer, j_Integer, k_Integer, n_Integer] := Which[Min[i, j, k, n] < 0 || Max[i, j, k] > n, 0, n == 0, KroneckerDelta[i, j, k, n], True, aux[i, j, k, n] = aux[-1 + i, j, k, -1 + n] + aux[-1 + i, 1 + j, 1 + k, -1 + n] + aux[i, -1 + j, k, -1 + n] + aux[1 + i, j, -1 + k, -1 + n] + aux[1 + i, 1 + j, -1 + k, -1 + n]]; Table[Sum[aux[i, j, k, n], {i, 0, n}, {j, 0, n}, {k, 0, n}], {n, 0, 10}]
|
|
|
CROSSREFS
|
Sequence in context: A149928 A003430 A149929 * A189924 A190908 A149931
Adjacent sequences: A149927 A149928 A149929 * A149931 A149932 A149933
|
|
|
KEYWORD
|
nonn,walk
|
|
|
AUTHOR
|
Manuel Kauers, Nov 18 2008
|
|
|
STATUS
|
approved
|
| |
|
|
