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 A058158 Triangle read by rows: T(n,k) is the number of labeled monoids of order n with k idempotents and a fixed identity. 4
 1, 1, 1, 1, 6, 4, 4, 45, 72, 35, 6, 528, 1308, 1676, 604, 80, 19935, 39700, 70170, 62060, 16727, 120, 3599436, 1969470, 3829000, 5167800, 3260382, 681232, 2760, 6085914205, 281840664, 294812385, 481221020, 482447637, 228315640, 38187291 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 LINKS Table of n, a(n) for n=1..36. Index entries for sequences related to monoids FORMULA T(n,k) = A058157(n,k)/n. EXAMPLE Triangle begins: 1; 1, 1; 1, 6, 4; 4, 45, 72, 35; 6, 528, 1308, 1676, 604; 80, 19935, 39700, 70170, 62060, 16727; ... CROSSREFS Row sums give A058154. Column 1: A058163. Main diagonal is A351730(n-1). Cf. A058137 (isomorphism classes), A058157, A058160 (commutative), A058166. Sequence in context: A330934 A019174 A019166 * A249185 A021159 A106332 Adjacent sequences: A058155 A058156 A058157 * A058159 A058160 A058161 KEYWORD nonn,tabl AUTHOR Christian G. Bower, Nov 14 2000 EXTENSIONS a(30)-a(36) from Andrew Howroyd, Feb 15 2022 STATUS approved

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Last modified September 12 11:08 EDT 2024. Contains 375850 sequences. (Running on oeis4.)