A123401 Number of maximal chains in the Stanley lattice of order n.

1, 1, 1, 18, 32400, 17146080000, 5838929512416000000, 2371384771694500507545600000000, 1912347371757319698802901729638809600000000000, 4729554291048229774403876712233157022270603395072000000000000000, 52408889027141714669562863434538278134100104813558451332105036103680000000000000000000

Offset

0,4

References

D. E. Knuth, TAOCP, Section 7.2.1.6, Problem 34.

Links

Table of n, a(n) for n=0..10.

Formula

(n*(n-1)/2)! * Product( (2*i-1)^(n-i),i=1..n-1).

Maple

f:=n-> (n*(n-1)/2)! * mul( (2*i-1)^(n-i), i=1..n-1);

Crossrefs

Sequence in context: A202155 A296653 A255406 * A201494 A079303 A159445

Adjacent sequences: A123398 A123399 A123400 * A123402 A123403 A123404

Keyword

nonn

Author

N. J. A. Sloane, Oct 15 2006

Status

approved