A046674 a(n) = A046673(n)/2.

1, 18, 660, 42000, 4142880, 586776960, 113020427520, 28432576972800, 9056055981772800, 3562946373482496000, 1697172166720622592000, 962691052768668647424000, 641260394342965606809600000, 495681727573700350908825600000, 440084864982859007245221888000000

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn

Crossrefs

Cf. A000254, A049034, A046673.

Extensions

Offset changed to 1 by Jon E. Schoenfield, Mar 08 2020