|
| |
|
|
A151430
|
|
Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of n steps taken from {(-1, -1), (-1, 0), (0, 1), (1, -1), (1, 0)}
|
|
0
| |
|
|
1, 1, 2, 7, 19, 61, 224, 771, 2855, 11005, 41963, 165661, 664443, 2674101, 10955892, 45281419, 188288455, 790957165, 3343062477, 14209485769, 60792612875, 261330644741, 1128597807923, 4896682653677, 21327006074731, 93233880458581, 409028951228459, 1800105977084221, 7946053746358811
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,3
|
|
|
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, 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[Sum[aux[0, k, n], {k, 0, n}], {n, 0, 25}]
|
|
|
CROSSREFS
| Sequence in context: A030224 A114624 A091024 * A083309 A164979 A080873
Adjacent sequences: A151427 A151428 A151429 * A151431 A151432 A151433
|
|
|
KEYWORD
| nonn,walk
|
|
|
AUTHOR
| Manuel Kauers (manuel(AT)kauers.de), Nov 18 2008
|
| |
|
|
