|
%I #15 Feb 02 2023 15:25:52
%S 1,0,1,3,4,3,978,1485,729,138,56630832,75503872,37755904,8390656,
%T 700688,813802235250650,1017252851596875
%N Triangle: T(n,k), k<=n: groupoids with n elements and k idempotents.
%H <a href="/index/Gre#groupoids">Index entries for sequences related to groupoids</a>
%e Triangle begins:
%e 1;
%e 0, 1;
%e 3, 4, 3;
%e 978, 1485, 729, 138;
%e 56630832, 75503872, 37755904, 8390656, 700688;
%e ...
%Y Row sums are A001329.
%Y Main diagonal is A030247.
%Y Columns k=0..1 are A030250, A030253.
%K nonn,tabl,more
%O 0,4
%A _Christian G. Bower_, May 15 1998
|
