|
Search: id:A071716
|
|
|
| A071716 |
|
Expansion of (1+x^2*C)*C, where C = (1-(1-4*x)^(1/2))/(2*x) is g.f. for Catalan numbers, A000108. |
|
+0
4
|
|
| 1, 1, 3, 7, 19, 56, 174, 561, 1859, 6292, 21658, 75582, 266798, 950912, 3417340, 12369285, 45052515, 165002460, 607283490, 2244901890, 8331383610, 31030387440, 115948830660, 434542177290, 1632963760974, 6151850548776
(list; graph; listen)
|
|
|
OFFSET
|
0,3
|
|
|
COMMENT
|
a(n) = number of lattice paths of n up steps and n down steps that start at the origin with an up step and do not cross the x-axis except possibly at (2n-2,0). - David Callan (callan(AT)stat.wisc.edu), Mar 14 2004
|
|
FORMULA
|
a(n) = C_n + C_(n-1) (Catalan numbers). - David Callan (callan(AT)stat.wisc.edu), Mar 14 2004
|
|
CROSSREFS
|
Essentially the same as A005807.
Sequence in context: A104522 A115760 A100702 this_sequence A005506 A051139 A049423
Adjacent sequences: A071713 A071714 A071715 this_sequence A071717 A071718 A071719
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
njas, Jun 06 2002
|
|
|
Search completed in 0.002 seconds
|
