|
| |
|
|
A026674
|
|
a(n) = T(2n-1,n-1) = T(2n,n+1), T given by A026725.
|
|
4
| |
|
|
1, 4, 16, 65, 267, 1105, 4597, 19196, 80380, 337284, 1417582, 5965622, 25130844, 105954110, 447015744, 1886996681, 7969339643, 33670068133, 142301618265, 601586916703, 2543852427847, 10759094481491, 45513214057191, 192560373660245
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
REFERENCES
| Paul Barry, A Catalan Transform and Related Transformations on Integer Sequences, Journal of Integer Sequences, Vol. 8 (2005), Article 05.4.5.
|
|
|
LINKS
| Rob Arthan, Comments on A026674, A026725, A026670
|
|
|
FORMULA
| G.f.: 1/2*[(1-x)/(sqrt(1-4x)-x)-1] (conjectured). - Ralf Stephan, Feb 05 2004
G.f.: xc(x)^3/(1-x*c(x)^3)=(1-5x-(1-x)sqrt(1-4x))/(2(x^2+4x-1)), c(x) the g.f. of A000108; - Paul Barry (pbarry(AT)wit.ie), Mar 19 2007
a(n) = the upper left term in M^n, where M is the following infinite square production matrix:
1, 1, 0, 0, 0, 0, 0,...
3, 1, 1, 0, 0, 0, 0,...
6, 1, 1, 1, 0, 0, 0,...
10, 1, 1, 1, 1, 0, 0,...
15, 1, 1, 1, 1, 1, 0,...
21, 1, 1, 1, 1, 1, 1,...
...
- Gary W. Adamson, Jul 11 2011
|
|
|
CROSSREFS
| Also a(n) = T(2n-1, n-1), T given by A026670.
Sequence in context: A012781 A132820 A165201 * A099781 A026872 A081915
Adjacent sequences: A026671 A026672 A026673 * A026675 A026676 A026677
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Clark Kimberling (ck6(AT)evansville.edu)
|
| |
|
|
