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A078820 20*C(2n,n)*(2n+1)/(n+4). 3
5, 24, 100, 400, 1575, 6160, 24024, 93600, 364650, 1421200, 5542680, 21633248, 84504875, 330372000, 1292646000, 5061729600, 19835652870, 77786874000, 305254551000, 1198665468000, 4709756401350, 18516070880736 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..21.

FORMULA

a(n) =a(n-1)*(4n^2+14n+6)/(n^2+4n) =A078817(3, n) =(2n+1)*A078819(n)/7 =20*A002457(n)/(n+4).

EXAMPLE

a(5)=20*C(10,5)*11/9=6160.

MATHEMATICA

Table[20Binomial[2n, n] (2n+1)/(n+4), {n, 0, 30}] (* Harvey P. Dale, Nov 02 2011 *)

CROSSREFS

Cf. A001700, A001791, A007946.

Sequence in context: A099653 A270126 A276139 * A291395 A179417 A181305

Adjacent sequences:  A078817 A078818 A078819 * A078821 A078822 A078823

KEYWORD

nonn

AUTHOR

Henry Bottomley, Dec 07 2002

STATUS

approved

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Last modified October 18 07:19 EDT 2019. Contains 328146 sequences. (Running on oeis4.)