A058144 Triangle: Number of self-converse monoids of order n with k idempotents.

1, 1, 1, 1, 3, 1, 2, 9, 6, 2, 1, 28, 31, 18, 6, 2, 131, 160, 132, 65, 19, 1, 1081, 947, 917, 612, 275, 68, 5

Offset

1,5

Links

Table of n, a(n) for n=1..29.

Index entries for sequences related to monoids

Example

The triangle begins as:
  1;
  1,  1;
  1,  3,  1;
  2,  9,  6,  2;
  1, 28, 31, 18, 6;
  ...

Crossrefs

Row sums give A058132. Main diagonal: A058122(n-1). Columns 1-3: A000001, A058145, A058146.

Sequence in context: A074308 A237186 A058142 * A378813 A132323 A305097

Adjacent sequences: A058141 A058142 A058143 * A058145 A058146 A058147

Keyword

nonn,tabl,more

Author

Christian G. Bower, Nov 14 2000

Status

approved