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 A090603 Number of n-element labeled groupoids with a fixed identity. 2

%I

%S 1,2,81,262144,152587890625,28430288029929701376,

%T 2651730845859653471779023381601,

%U 178405961588244985132285746181186892047843328,11790184577738583171520872861412518665678211592275841109096961

%N Number of n-element labeled groupoids with a fixed identity.

%C Also labeled partial groupoids with n-1 elements.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Groupoid.html">Groupoid.</a>

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

%F a(n) = n^((n-1)^2). - _Alois P. Heinz_, Jul 30 2012

%p seq(mul(mul(k*n/j,j=2..n), k=2..n), n=0..9); # _Zerinvary Lajos_, Jun 01 2007

%p a:=n->mul(mul(sum(1, j=0..n), k=1..n), m=1..n): seq(a(n), n=0..7); # _Zerinvary Lajos_, Dec 31 2008

%p with(finance):seq(futurevalue(1,n,n^2),n=0..8); # _Zerinvary Lajos_, Mar 25 2009

%t Table[n^(n-1)^2,{n,10}] (* _Harvey P. Dale_, May 31 2019 *)

%K nonn

%O 1,2

%A _Christian G. Bower_, Dec 05 2003

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Last modified April 5 13:02 EDT 2020. Contains 333241 sequences. (Running on oeis4.)