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Search: id:A058167
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| A058167 |
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Triangle: Labeled commutative semigroups of order n with k idempotents. |
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+0
1
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| 1, 4, 2, 24, 30, 9, 260, 492, 312, 76, 4805, 10060, 9900, 4900, 1065, 157956, 284130, 348420, 259500, 112500, 22566, 12277440, 11892846, 14768775, 14093380, 9063600, 3592554, 674611
(list; table; graph; listen)
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OFFSET
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1,2
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LINKS
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Index entries for sequences related to semigroups
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EXAMPLE
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1; 4,2; 24,30,9; 260,492,312,76; 4805,10060,9900,4900,1065; ...
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CROSSREFS
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Row sums give A023815. Main diagonal: A058164(n+1).
Sequence in context: A100400 A030211 A134461 this_sequence A140331 A095896 A123670
Adjacent sequences: A058164 A058165 A058166 this_sequence A058168 A058169 A058170
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KEYWORD
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nonn,tabl,hard
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AUTHOR
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Christian G. Bower (bowerc(AT)usa.net), Nov 15 2000
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