A039931 Number of different sets of parameters for mixed orthogonal arrays with n runs and strength 2.

1, 2, 2, 5, 2, 5, 2, 14, 6, 5, 2, 23, 2, 5, 5, 61, 2, 26, 2, 35, 5, 5, 2

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• nice
• more

Comments

a(36) is the first unknown term.

Examples

			For 12 runs there are 23 different sets of parameters: 12^1, 2^k with 1 <= k <= 11, 3^1*2^k with 0 <= k <= 4, 6^1*2^k with 0 <= k <= 2, 4^1*3^1, 4^1 and 1^1.
		

References

• A. S. Hedayat, N. J. A. Sloane and J. Stufken, Orthogonal Arrays, Springer-Verlag, NY, 1999.

Links

• E. M. Rains, N. J. A. Sloane and J. Stufken, The Lattice of N-Run Orthogonal Arrays, J. Stat. Planning Inference, 102 (2002), 477-500 (Abstract, pdf, ps).
• Eric D. Schoen, Pieter T. Eendebak and Man V. M. Nguyen, Complete enumeration of pure-level and mixed-level orthogonal arrays, Journal of Combinatorial Designs, Volume 18, Issue 2, pages 123-140, March 2010; DOI: 10.1002/jcd.20236; Correction: Journal of Combinatorial Designs, Volume 18, Issue 6, page 488, November 2010; DOI: 10.1002/jcd.20270.

Crossrefs

Cf. A039927, A039930.

Extensions

Needs to be updated using the results of Schoen et al. (2010). - N. J. A. Sloane, Feb 21 2013