login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A004677 Numerator of 2^n*(3*n-3)!/( ((n-1)!)^3 * (2*n)! ). 4
1, 1, 1, 2, 11, 91, 17, 323, 4807, 3289, 8671, 11687, 15283, 10743949, 15189721, 21069613, 1339779509, 1339779509, 101007559, 101007559, 4215217889, 185371558793, 8059632991, 11489264051, 815737747621, 2203307656324321, 41571842572157, 3284175563200403 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

REFERENCES

Valtr, Pavel; The probability that n random points in a triangle are in convex position. Combinatorica 16 (1996), no. 4, 567-573.

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..1000

Eric Weisstein's World of Mathematics, Sylvester's Four-Point Problem.

MATHEMATICA

Table[Numerator[2^n*(3*n - 3)!/(((n - 1)!)^3*(2*n)!)], {n, 1, 50}] (* G. C. Greubel, Oct 12 2018 *)

PROG

(PARI) for(n=1, 50, print1(numerator(2^n*(3*n - 3)!/(((n - 1)!)^3*(2*n)!)), ", ")) \\ G. C. Greubel, Oct 12 2018

(MAGMA) [Numerator(2^n*Factorial(3*n - 3)/((Factorial(n - 1))^3*Factorial(2*n))): n in [1..50]]; // G. C. Greubel, Oct 12 2018

CROSSREFS

Cf. A000139, A004824 (denominators).

Sequence in context: A197914 A138552 A258221 * A266656 A094955 A143870

Adjacent sequences:  A004674 A004675 A004676 * A004678 A004679 A004680

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 26 14:18 EST 2021. Contains 341632 sequences. (Running on oeis4.)