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Number of labeled lattices with fixed a fixed bottom and top.
1

%I #10 Jan 02 2020 13:56:47

%S 1,1,3,19,213,3761,96373,3377487,154874569,8980530625,641008120761,

%T 55110586506119,5606337607922197,664893010179107529,

%U 90785224148218811149,14119839142088335522351,2478547355267024762146257

%N Number of labeled lattices with fixed a fixed bottom and top.

%F a(n) = A055512(n)/(n*(n-1)) = A058164(n)/(n-1).

%t A055512 = Cases[Import["https://oeis.org/A055512/b055512.txt", "Table"], {_, _}][[All, 2]];

%t a[n_] := A055512[[n+1]]/(n(n-1));

%t a /@ Range[2, 18] (* _Jean-François Alcover_, Jan 02 2020 *)

%Y Cf. A055512, A058164.

%K nonn,hard,more

%O 2,3

%A _Christian G. Bower_, Nov 15 2000

%E a(18) from _Jean-François Alcover_, Jan 02 2020