A008380 4*(2n-1)!*H(2n), where H(n) = Sum 1/i are harmonic numbers.

6, 50, 1176, 54792, 4251456, 495480960, 80990184960, 17683570598400, 4972664013004800, 1750589607352320000, 754268505333719040000, 390464536066453094400000, 239146855253471119933440000

Offset

1,1

Links

Table of n, a(n) for n=1..13.

Crossrefs

Sequence in context: A361193 A363315 A058784 * A196905 A066303 A301436

Adjacent sequences: A008377 A008378 A008379 * A008381 A008382 A008383

Keyword

nonn

Author

N. J. A. Sloane.

Status

approved