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A124079
a(n) = H(2n+1)*(2n+1)!/n!, where H(n) = Sum_{k=1..n} 1/k, the n-th harmonic number.
2
1, 11, 137, 2178, 42774, 1004532, 27503832, 860945040, 30342400560, 1189277851680, 51324077044800, 2418504655996800, 123569793528249600, 6804789307610918400, 401797276566253747200, 25323878997135577958400
OFFSET
0,2
MAPLE
H:=n->sum(1/k, k=1..n): a:=n->(2*n+1)!*H(2*n+1)/n!: seq(a(n), n=0..17); # Emeric Deutsch, Nov 28 2006
MATHEMATICA
f[n_] := HarmonicNumber[2n + 1](2n + 1)!/n!; Table[f@n, {n, 0, 15}] (* Robert G. Wilson v, Nov 26 2006 *)
CROSSREFS
Sequence in context: A142895 A232180 A201111 * A174289 A003378 A142930
KEYWORD
easy,nonn
AUTHOR
Leroy Quet, Nov 24 2006
EXTENSIONS
More terms from Robert G. Wilson v, Nov 26 2006
More terms from Emeric Deutsch, Nov 28 2006
STATUS
approved