|
Search: id:A004990
|
|
|
| A004990 |
|
(3^n/n!)*product[ k=0..n-1 ](3*k - 1). |
|
+0
4
|
|
| 1, -3, -9, -45, -270, -1782, -12474, -90882, -681615, -5225715, -40760577, -322379109, -2579032872, -20830650120, -169621008120, -1390892266584, -11474861199318, -95173848770814, -793115406423450, -6637123664280450, -55751838779955780
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
FORMULA
|
A(x) = (1 - 9*x)^(1/3).
a(n) ~ -1/3*Gamma(2/3)^-1*n^(-4/3)*3^(2*n)*{1 + 2/9*n^-1 + ...}.
|
|
PROGRAM
|
(PARI): for(n=0, 30, print1( (3^n/n!)*prod(k=0, n-1, (3*k-1) ), ", "))
|
|
CROSSREFS
|
a(n)=9*A034164(n-2), n >= 2.
Sequence in context: A103620 A138315 A038059 this_sequence A027616 A013492 A106341
Adjacent sequences: A004987 A004988 A004989 this_sequence A004991 A004992 A004993
|
|
KEYWORD
|
sign,easy
|
|
AUTHOR
|
Joe Keane (jgk(AT)jgk.org)
|
|
EXTENSIONS
|
More terms from Jason Earls (zevi_35711(AT)yahoo.com), Dec 03 2001
|
|
|
Search completed in 0.002 seconds
|
