A112101 Number of interval orders of magnitude n having no duplicate holdings (NODH).

1, 3, 10, 58, 722, 19826, 1161882, 141436842, 35192653666, 17733070720738, 17997787816364330, 36678689328450847514, 149831453090755680149490, 1225618861520566592060441682, 20064594684596858150355969600442, 657195622713393693107201875915723402

Offset: 0

Author

N. J. A. Sloane, Nov 28 2005

Keywords

• nonn

References

• W. T. Trotter, Combinatorics and Partially Ordered Sets, Johns Hopkins, 1992; see p. 195.

Formula

a(n) = Sum_{k=0..n} binomial(n, k)*A111491(k).