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Triangle: T(n,k), k<=n: commutative groupoids with no symmetry with n elements and k idempotents.
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%I #10 Dec 19 2015 09:51:04

%S 1,0,1,1,2,1,35,51,27,3,13776,18330,9152,2016,164,83306272,104124850,

%T 52056277,13006746,1622527,80461

%N Triangle: T(n,k), k<=n: commutative groupoids with no symmetry with n elements and k idempotents.

%H <a href="/index/Gre#groupoids">Index entries for sequences related to groupoids</a>

%Y Cf. A001329, A001425, A030258, A030261, A030264.

%K nonn,tabl,more

%O 0,5

%A _Christian G. Bower_, May 15 1998