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A078820
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20*C(2n,n)*(2n+1)/(n+4).
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2
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5, 24, 100, 400, 1575, 6160, 24024, 93600, 364650, 1421200, 5542680, 21633248, 84504875, 330372000, 1292646000, 5061729600, 19835652870, 77786874000, 305254551000, 1198665468000, 4709756401350, 18516070880736
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listen;
history;
text;
internal format)
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OFFSET
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0,1
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LINKS
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Table of n, a(n) for n=0..21.
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FORMULA
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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).
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EXAMPLE
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a(5)=20*C(10,5)*11/9=6160.
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MATHEMATICA
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Table[20Binomial[2n, n] (2n+1)/(n+4), {n, 0, 30}] (* From Harvey P. Dale, Nov 02 2011 *)
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CROSSREFS
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Cf. A001700, A001791, A007946.
Sequence in context: A212349 A087095 A099653 * A179417 A181305 A046724
Adjacent sequences: A078817 A078818 A078819 * A078821 A078822 A078823
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KEYWORD
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nonn
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AUTHOR
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Henry Bottomley, Dec 07 2002
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STATUS
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approved
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