|
| |
|
|
A066380
|
|
Sum_{k=0..n} C(3*n,k).
|
|
3
| |
|
|
1, 4, 22, 130, 794, 4944, 31180, 198440, 1271626, 8192524, 53009102, 344212906, 2241812648, 14637774688, 95786202688, 628002401520, 4124304597834, 27126202533252, 178651732923346, 1178005033926998, 7776048412324714
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,2
|
|
|
REFERENCES
| R. L. Graham, D. E. Knuth and O. Patashnik, Concrete Mathematics. Addison-Wesley, Reading, MA, 1990, p. 425.
|
|
|
LINKS
| Harry J. Smith, Table of n, a(n) for n=0,...,150
|
|
|
FORMULA
| a(n) ~ C(3n, n)(2 - 4/n + O(1/n^2)).
G.f.: (1-g)/((3*g-1)*(2*g-1)) where g*(1-g)^2 = x. - Mark van Hoeij, Nov 10 2011
|
|
|
PROG
| (PARI) { for (n=0, 150, a=0; for (k=0, n, a+=binomial(3*n, k)); write("b066380.txt", n, " ", a) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Feb 12 2010]
|
|
|
CROSSREFS
| Cf. A032443, A066381.
Sequence in context: A086682 A155862 A088536 * A180899 A007195 A193620
Adjacent sequences: A066377 A066378 A066379 * A066381 A066382 A066383
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Dec 23 2001
|
| |
|
|
