cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-4 of 4 results.

A048164 a(0)=1, a(n+1)=1+(2^(2^n)+1)*a(n).

Original entry on oeis.org

1, 4, 21, 358, 92007, 6029862760, 25898063359598159721, 477734946799221833229035410333259818858, 162564778457687820218065957445498785826947155451688293007128627114802460256107
Offset: 0

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Author

N. J. A. Sloane, E. M. Rains

Keywords

Comments

a(n) = height of lattice of orthogonal arrays with 2^2^n runs.

Crossrefs

Programs

  • Mathematica
    RecurrenceTable[{a[0]==1,a[n]==1+(2^(2^(n-1))+1)a[n-1]},a,{n,10}] (* Harvey P. Dale, Dec 13 2013 *)

Formula

a(n) converges to nearest integer to c*(2^(2^n)-1), where c = 1.403936827882178... (see A048649).

A039927 Number of types of maximal mixed orthogonal arrays with n runs.

Original entry on oeis.org

0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 4, 1, 1, 1, 2, 1, 2, 1, 4, 1, 1, 1
Offset: 1

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Author

Keywords

Comments

Number of dual atoms in lattice of parameters of mixed orthogonal arrays with n runs and strength 2.
a(36) is the first unknown term.

References

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

Crossrefs

Extensions

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

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

Original entry on oeis.org

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

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Author

Keywords

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.

Crossrefs

Extensions

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

A048638 Height of lattice of parameters of mixed orthogonal arrays with 2^n runs and strength 2.

Original entry on oeis.org

1, 4, 9, 21, 42, 86, 171, 358, 715, 1431
Offset: 0

Views

Author

N. J. A. Sloane, E. M. Rains, J. Stufken

Keywords

Crossrefs

Showing 1-4 of 4 results.