|
| |
|
|
A006957
|
|
Self-convolution of numbers of preferential arrangements.
|
|
0
| |
|
|
1, 2, 7, 32, 185, 1310, 11067, 109148, 1234045, 15752858, 224169407, 3518636504, 60381131265, 1124390692886, 22577494959427, 486212633129300, 11177317486573445, 273173247028616594, 7072436847620016327
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,2
|
|
|
MAPLE
| f:= proc(n) option remember; `if`(n<=1, 1, add (binomial (n, k) *f(n-k), k=1..n)) end: a:= n-> add (f(k) *f(n-k), k=0..n): seq (a(n), n=0..25); [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Feb 02 2009]
|
|
|
CROSSREFS
| Cf. A000670.
Sequence in context: A000153 A006154 A000987 * A189780 A195983 A079265
Adjacent sequences: A006954 A006955 A006956 * A006958 A006959 A006960
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
|
|
|
EXTENSIONS
| More terms from Alois P. Heinz (heinz(AT)hs-heilbronn.de), Feb 02 2009
|
| |
|
|
