|
| |
|
|
A151350
|
|
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, 1)}
|
|
0
| |
|
|
1, 0, 1, 1, 6, 17, 58, 202, 749, 2901, 11318, 45171, 183265, 756196, 3159230, 13341971, 56903856, 244855696, 1061995972, 4638725316, 20391632508, 90164737708, 400807229526, 1790417941480, 8033839546376, 36198663913941, 163730600062179, 743218114133634, 3384894808811735, 15463955571145905
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,5
|
|
|
LINKS
| M. Bousquet-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, -1 + 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: A088016 A010330 A109311 * A195741 A006758 A123189
Adjacent sequences: A151347 A151348 A151349 * A151351 A151352 A151353
|
|
|
KEYWORD
| nonn,walk
|
|
|
AUTHOR
| Manuel Kauers (manuel(AT)kauers.de), Nov 18 2008
|
| |
|
|
