|
Search: id:A034723
|
|
|
| A034723 |
|
One third of sextic factorial numbers. |
|
+0
8
|
|
| 1, 9, 135, 2835, 76545, 2525985, 98513415, 4433103675, 226088287425, 12887032383225, 811883040143175, 56019929769879075, 4201494732740930625, 340321073352015380625, 29607933381625338114375
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
FORMULA
|
3*a(n) = (6*n-3)(!^6) := product(6*j-3, j=1..n) = 3^n*A001147(n) = 3^n*(2*n)!/(2^n*n!), A001147(n)=(2*n-1)!!; E.g.f. (-1+(1-6*x)^(-1/2))/3.
|
|
MATHEMATICA
|
s=1; lst={s}; Do[s+=n*s; AppendTo[lst, s], {n, 8, 5!, 6}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Nov 08 2008]
|
|
CROSSREFS
|
Cf. A008542, A034689.
Sequence in context: A082760 A112426 A163200 this_sequence A052137 A003376 A156975
Adjacent sequences: A034720 A034721 A034722 this_sequence A034724 A034725 A034726
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de)
|
|
|
Search completed in 0.002 seconds
|
