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A038018 Triangle: T(n,k), k<=n: groupoids with n elements and k idempotents. 3
1, 0, 1, 3, 4, 3, 978, 1485, 729, 138, 56630832, 75503872, 37755904, 8390656, 700688, 813802235250650, 1017252851596875 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Table of n, a(n) for n=0..16.

Index entries for sequences related to groupoids

CROSSREFS

Cf. A001329, A030247, A030250, A030253.

Sequence in context: A288404 A287986 A190959 * A108658 A240669 A213201

Adjacent sequences:  A038015 A038016 A038017 * A038019 A038020 A038021

KEYWORD

nonn,tabl

AUTHOR

Christian G. Bower, May 15 1998

STATUS

approved

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Last modified February 16 21:46 EST 2020. Contains 331975 sequences. (Running on oeis4.)