A058142 - OEIS

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A058142

Triangle read by rows: number of commutative monoids of order n with k idempotents.

6

1, 1, 1, 1, 3, 1, 2, 9, 6, 2, 1, 26, 30, 16, 5, 1, 98, 142, 111, 54, 15, 1, 455, 718, 713, 482, 215, 53, 3, 4018, 4277, 4637, 3919, 2414, 996, 222, 2, 101910, 36124, 32937, 31308, 24047, 13758, 5294, 1078, 1, 10054303, 708355, 290278, 260758, 229411, 164216, 88178, 31867, 5994

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OFFSET

1,5

LINKS

Table of n, a(n) for n=1..55.

Index entries for sequences related to monoids

EXAMPLE

Triangle begins:

1;

1, 1;

1, 3, 1;

2, 9, 6, 2;

1, 26, 30, 16, 5;

1, 98, 142, 111, 54, 15;

...

CROSSREFS

Row sums give A058131.

Main diagonal: A006966.

Columns 1..2: A000688, A058143.

Cf. A058116, A058137, A058150, A058159, A058160.

Sequence in context: A238388 A074308 A237186 * A058144 A132323 A305097

Adjacent sequences: A058139 A058140 A058141 * A058143 A058144 A058145

KEYWORD

nonn,tabl,hard

AUTHOR

Christian G. Bower, Nov 14 2000

EXTENSIONS

a(30)-a(55) from Andrew Howroyd, Feb 15 2022

STATUS

approved