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.

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A000315 Number of reduced Latin squares of order n; also number of labeled loops (quasigroups with an identity element) with a fixed identity element.

Original entry on oeis.org

1, 1, 1, 4, 56, 9408, 16942080, 535281401856, 377597570964258816, 7580721483160132811489280, 5363937773277371298119673540771840
Offset: 1

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Author

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Comments

A reduced Latin square of order n is an n X n matrix where each row and column is a permutation of 1..n and the first row and column are 1..n in increasing order. - Michael Somos, Mar 12 2011
The Stones-Wanless (2010) paper shows among other things that a(n) is 0 mod n if n is composite and 1 mod n if n is prime.

References

  • L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 183.
  • J. Denes, A. D. Keedwell, editors, Latin Squares: new developments in the theory and applications, Elsevier, 1991, pp. 1, 388.
  • R. A. Fisher and F. Yates, Statistical Tables for Biological, Agricultural and Medical Research. 6th ed., Hafner, NY, 1963, p. 22.
  • C. R. Rao, S. K. Mitra and A. Matthai, editors, Formulae and Tables for Statistical Work. Statistical Publishing Society, Calcutta, India, 1966, p. 193.
  • J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 210.
  • H. J. Ryser, Combinatorial Mathematics. Mathematical Association of America, Carus Mathematical Monograph 14, 1963, pp. 37, 53.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
  • M. B. Wells, Elements of Combinatorial Computing. Pergamon, Oxford, 1971, p. 240.

Crossrefs

Formula

a(n) = A002860(n) / (n! * (n-1)!) = A000479(n) / (n-1)!.

Extensions

Added June 1995: the 10th term was probably first computed by Eric Rogoyski
a(11) (from the McKay-Wanless article) from Richard Bean, Feb 17 2004

A057771 Number of loops (quasigroups with an identity element) of order n.

Original entry on oeis.org

0, 1, 1, 1, 2, 6, 109, 23746, 106228849, 9365022303540, 20890436195945769617, 1478157455158044452849321016
Offset: 0

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Author

Christian G. Bower, Nov 01 2000

Keywords

Crossrefs

Extensions

a(8) from Juergen Buntrock (jubu(AT)jubu.com), Nov 03 2003.
a(9)-a(10) (from the McKay-Meynert-Myrvold article) from Richard Bean, Feb 17 2004
a(11) from Petteri Kaski (petteri.kaski(AT)cs.helsinki.fi), Sep 18 2009
a(0) prepended by Jianing Song, Oct 26 2019
Showing 1-2 of 2 results.