A124079 a(n) = H(2n+1)*(2n+1)!/n!, where H(n) = Sum_{k=1..n} 1/k, the n-th harmonic number.

1, 11, 137, 2178, 42774, 1004532, 27503832, 860945040, 30342400560, 1189277851680, 51324077044800, 2418504655996800, 123569793528249600, 6804789307610918400, 401797276566253747200, 25323878997135577958400

Offset

0,2

Links

Table of n, a(n) for n=0..15.

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

Cf. A123989, A124078.

Sequence in context: A142895 A232180 A201111 * A174289 A003378 A142930

Adjacent sequences: A124076 A124077 A124078 * A124080 A124081 A124082

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