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A058148
Monoids of order n with 2 idempotents, considered to be equivalent when they are isomorphic or anti-isomorphic (by reversal of the operator).
1
1, 3, 9, 30, 175, 3333
OFFSET
2,2
CROSSREFS
Column 2 of A058147.
Sequence in context: A003604 A357615 A292300 * A031031 A371831 A306526
KEYWORD
nonn,more
AUTHOR
Christian G. Bower, Nov 14 2000
STATUS
approved