|
Search: id:A106540
|
|
|
| A106540 |
|
a(n)= a(n-1)-2*a(n-2)-3*a(n-3)-...-(n-1)*a(1), beginning with 1. |
|
+0
2
|
|
| 1, 1, -1, -6, -11, -5, 28, 87, 111, -46, -519, -1105, -812, 2051, 8003, 12130, 477, -43213, -107764, -106273, 133575, 716562, 1269265, 492135, -3436796, -10232533, -12529349, 6701026, 62284757, 128290443, 86849596, -256333913, -946668833
(list; graph; listen)
|
|
|
OFFSET
|
1,4
|
|
|
COMMENT
|
To accommodate the first three terms, the conjectured generating function must be changed to -1/2+(1/2)*(1-x+x^2)/(1-3x+5x^2-2x^3). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 22 2008]
|
|
FORMULA
|
G.f.: (2*x^2 - 3*x - 1)/(-2*x^3 + 5*x^2 - 3*x + 1) (conjectured).
|
|
EXAMPLE
|
a(5)=-6-2*(-1)-3*1-4*1=-6+2-3-4=-11
|
|
CROSSREFS
|
Sequence in context: A115677 A100129 A009443 this_sequence A134012 A103704 A135998
Adjacent sequences: A106537 A106538 A106539 this_sequence A106541 A106542 A106543
|
|
KEYWORD
|
easy,sign
|
|
AUTHOR
|
Alexandre Wajnberg (alexandre.wajnberg(AT)ulb.ac.be), May 08 2005
|
|
EXTENSIONS
|
Extended beyond a(14) by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 22 2008
|
|
|
Search completed in 0.002 seconds
|
