Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A001427
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A001427 Number of regular semigroups of order n.
(Formerly M2823 N1136)
+0
1
1, 3, 9, 42, 206, 1352, 10168 (list; graph; listen)
OFFSET

1,2

REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

H. Juergensen and P. Wick, Die Halbgruppen von Ordnungen <= 7, Semigroup Forum, 14 (1977), 69-79.

R. J. Plemmons, There are 15973 semigroups of order 6, Math. Algor., 2 (1967), 2-17; 3 (1968), 23.

R. J. Plemmons, Cayley Tables for All Semigroups of Order Less Than 7. Department of Mathematics, Auburn Univ., 1965.

LINKS

Index entries for sequences related to semigroups

CROSSREFS

Sequence in context: A113271 A057724 A129879 this_sequence A020128 A018965 A018995

Adjacent sequences: A001424 A001425 A001426 this_sequence A001428 A001429 A001430

KEYWORD

nonn,nice

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified November 23 17:09 EST 2009. Contains 167438 sequences.


AT&T Labs Research