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.

User: Martin P Kidd

Martin P Kidd's wiki page.

Martin P Kidd has authored 10 sequences.

A181592 Number of isomorphism classes of idempotent self-orthogonal Latin squares of order n.

Original entry on oeis.org

1, 0, 0, 1, 2, 0, 8, 8, 283, 243284
Offset: 1

Author

Martin P Kidd, Nov 01 2010

Keywords

Comments

A self-orthogonal Latin square (SOLS) is a Latin square orthogonal to its transpose. Two SOLS L and L' are isomorphic if a permutation applied to the rows, columns and symbols of L maps L to L'.

References

  • G. P. Graham and C. E. Roberts, 2006. Enumeration and isomorphic classification of self-orthogonal Latin squares, Journal of Combinatorial Mathematics and Combinatorial Computing, 59, pp. 101-118.

A181593 Number of isomorphism classes of self-orthogonal Latin squares of order n.

Original entry on oeis.org

1, 0, 0, 6, 22, 0, 3972, 104120, 69112956, 881912947656
Offset: 1

Author

Martin P Kidd, Nov 01 2010

Keywords

Comments

A self-orthogonal Latin square (SOLS) is a Latin square orthogonal to its transpose. Two SOLS L and L' are isomorphic if a permutation applied to the rows, columns and symbols of L maps L to L'.

Extensions

a(10) from Martin Kidd, Oct 20 2011

A160366 Number of transpose-isomorphism classes of self-orthogonal Latin squares of order n.

Original entry on oeis.org

1, 0, 0, 5, 11, 0, 1986, 52060, 34564884, 440956473828
Offset: 1

Author

Martin P Kidd, May 11 2009

Keywords

Comments

A self-orthogonal Latin square (SOLS) is a Latin square orthogonal to its transpose. Two SOLS L and L' are (row,column)-paratopic if a permutation p applied to the rows and columns of L and a permutation q applied to the symbol set of L transforms L into L', in which case (p,q) is called an (row,column)-paratopism from L to L'. If p=q, then L and L' are transpose-isomorphic. An (row,column)-autoparatopism is an (row,column)-paratopism that maps L onto itself. The number of transpose-isomorphism classes of SOLS of order n may be determined by the formula sum_{L in I(n)} sum_{a in A(L)}y(a)/|A(L)| where I(n) is a set of (row,column)-paratopism class representatives of SOLS of order n, A(L) is the set of (row,column)-autoparatopism of L for which p and q are both of the same type (x_1,x_2,...,x_n) and y(a)=\prod_{i=1}^n x_i!i^{x_i}. A set of (row,column)-paratopism class representatives may be found at www.vuuren.co.za -> Repositories.

References

  • G. P. Graham and C.E. Roberts, 2006. Enumeration and isomorphic classification of self-orthogonal Latin squares, Journal of Combinatorial Mathematics and Combinatorial Computing, 59, pp. 101-118.

Crossrefs

Extensions

Class names corrected, references updated, and a link updated by Martin P Kidd, Aug 14 2010

A160367 Number of idempotent self-orthogonal Latin squares of order n.

Original entry on oeis.org

1, 0, 0, 2, 12, 0, 3840, 103680, 69088320, 881912908800
Offset: 1

Author

Martin P Kidd, May 11 2009

Keywords

Comments

A self-orthogonal Latin square (SOLS) is a Latin square orthogonal to its transpose and a SOLS L is idempotent if L(i,i)=i. Two SOLS L and L' are (row,column)-paratopic if a permutation p applied to the rows and columns of L and a permutation q applied to the symbol set of L transforms L into L', in which case (p,q) is an (row,column)-paratopism from L to L'. An (row,column)-autoparatopism is an (row,column)-paratopism that maps L to itself. The number of idempotent SOLS of order n may be found by the formula sum_{L in I(n)}2n!/|A(L)|, where I(n) is a set of (row,column)-paratopism class representatives of SOLS of order n and A(L) is the (row,column)-autoparatopism group of L. A set of (row,column)-paratopism class representatives may be found at www.vuuren.co.za -> Repositories.

References

  • G. P. Graham and C.E. Roberts, 2006. Enumeration and isomorphic classification of self-orthogonal Latin squares, Journal of Combinatorial Mathematics and Combinatorial Computing, 59, pp. 101-118.

Crossrefs

Extensions

Class names corrected, references updated, and a link updated by Martin P Kidd, Aug 14 2010

A160368 Number of self-orthogonal Latin squares of order n.

Original entry on oeis.org

1, 0, 0, 48, 1440, 0, 19353600, 4180377600, 25070769561600, 3200285563453440000
Offset: 1

Author

Martin P Kidd, May 11 2009

Keywords

Comments

A self-orthogonal Latin square is a Latin square orthogonal to its transpose and a SOLS L is idempotent if L(i,i)=i. The number of distinct SOLS of order n may be determined by multiplying the number of idempotent SOLS of order n by n!.

References

  • G. P. Graham and C.E. Roberts, 2006. Enumeration and isomorphic classification of self-orthogonal Latin squares, Journal of Combinatorial Mathematics and Combinatorial Computing, 59, pp. 101-118.

Crossrefs

Extensions

References updated and a link updated by Martin P Kidd, Aug 14 2010

A166488 Number of transpose-isomorphism classes of SOLSSOMs of order n.

Original entry on oeis.org

31, 749, 0, 1210622, 1248307242, 640121719688, 0
Offset: 4

Author

Martin P Kidd, Oct 21 2009

Keywords

Comments

A SOLSSOM is a self-orthogonal Latin square with a symmetric orthogonal mate. Two SOLSSOMs (L,S) and (L',S') are transpose-isomorphic if a permutation applied to the rows, columns and symbols of L and S maps (L,S) to (L',S') or (L'',S') (where L'' is the transpose of L').

References

  • A.P. Burger, M.P. Kidd and J.H. van Vuuren, Enumeration of self-orthogonal Latin squares with symmetric orthogonal mates, Submitted to LitNet Akademies (Natuurwetenskappe)

Crossrefs

Extensions

Class name and definition corrected by Martin P Kidd, Nov 01 2010

A166489 Number of standard SOLSSOMs of order n.

Original entry on oeis.org

2, 12, 0, 480, 374400, 3528000, 0
Offset: 4

Author

Martin P Kidd, Oct 21 2009

Keywords

Comments

A SOLSSOM is a self-orthogonal Latin square with a symmetric orthogonal mate. A SOLSSOM is standard if the self-orthogonal Latin square is idempotent and if the symmetric mate is reduced.

References

  • A.P. Burger, M.P. Kidd and J.H. van Vuuren, Enumeration of self-orthogonal Latin squares with symmetric orthogonal mates, Submitted to LitNet Akademies (Natuurwetenskappe)

Crossrefs

Extensions

Definition and number of order 8 (now includes non-unipotent SOLSSOMs) corrected by Martin P Kidd, Nov 01 2010

A166490 Number of SOLSSOMs of order n.

Original entry on oeis.org

1152, 172800, 0, 12192768000, 608662978560000, 464573723443200000, 0
Offset: 4

Author

Martin P Kidd, Oct 21 2009

Keywords

Comments

A SOLSSOM is a self-orthogonal Latin square with a symmetric orthogonal mate.

References

  • A.P. Burger, M.P. Kidd and J.H. van Vuuren, Enumeration of self-orthogonal Latin squares with symmetric orthogonal mates, Submitted to LitNet Akademies (Natuurwetenskappe)

Crossrefs

Extensions

Number for n=8 corrected by Martin P Kidd, Nov 01 2010

A160365 Number of (row,column)-paratopism classes of self-orthogonal Latin squares of order n.

Original entry on oeis.org

1, 0, 0, 1, 1, 0, 4, 4, 175, 121642
Offset: 1

Author

Martin P Kidd, May 11 2009

Keywords

Comments

A self-orthogonal Latin square (SOLS) is a Latin square orthogonal to its transpose. Two SOLS L and L' are (row,column)-paratopic if two permutations, one applied to the rows and columns of L and one applied to the symbol set of L, transforms L into L'. Enumeration of the (row,column)-paratopism classes of self-orthogonal Latin squares was performed via an (almost) exhaustive computerized tree search. A number of pruning rules was used to eliminate (row,column)-paratopisms and generate one SOLS from each (row,column)-paratopism class (a repository of these class representatives may found at www.vuuren.co.za -> Repositories). As validation of the results two different approaches to the search tree was implemented.

References

  • G. P. Graham and C.E. Roberts, 2006. Enumeration and Isomorphic Classification of Self-Orthogonal Latin Squares, Journal of Combinatorial Mathematics and Combinatorial Computing, 59, pp. 101-118.

Crossrefs

Extensions

Class names corrected by, References updated by, Link updated by Martin P Kidd, Aug 14 2010

A166487 Number of (row,column)-paratopism classes of SOLSSOMs of order n.

Original entry on oeis.org

1, 1, 0, 2, 32, 26, 0
Offset: 4

Author

Martin P Kidd, Oct 21 2009

Keywords

Comments

A SOLSSOM is a self-orthogonal Latin square with a symmetric orthogonal mate. Two SOLSSOMs (L,S) and (L',S') are (row,column)-paratopic if a permutation applied to the rows and columns of L and S and two permutations applied to the symbols of L and S, respectively, maps (L,S) to (L',S') or (L'',S') (where L'' is the transpose of L').

References

  • A.P. Burger, M.P. Kidd and J.H. van Vuuren, Enumeration of self-orthogonal Latin squares with symmetric orthogonal mates, Submitted to LitNet Akademies (Natuurwetenskappe)

Crossrefs

Extensions

Class names corrected, and results for not only unipotent SOLSSOMs provided by Martin P Kidd, Nov 01 2010