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%I #13 Nov 27 2018 04:46:04
%S 1,1,5,50,625,15625,1953125,488281250,152587890625,95367431640625,
%T 298023223876953125,1862645149230957031250,14551915228366851806640625,
%U 227373675443232059478759765625,17763568394002504646778106689453125,2775557561562891351059079170227050781250
%N Number of tilings of a fortress (or Penta-Aztec-Diamond) of order n.
%C The Lai (2013) article contains many other sequences which should be added to the OEIS (e.g. the sequences in Theorems 15, 18, 21, 22 and Corollary 20).
%H Tri Lai, <a href="http://www.combinatorics.org/ojs/index.php/eljc/article/view/v20i4p31">New aspects of regions whose tilings are enumerated by perfect powers</a>, Electronic Journal of Combinatorics, 20(4), 2013, #P31. See Th. 8.
%p f:=n-> if (n mod 2) = 0 then 5^((n/2)^2) elif (n mod 4) = 1 then 5^((n^2-1)/4) else 2*5^((n^2-1)/4); fi;
%p [seq(f(n),n=0..30)];
%K nonn
%O 0,3
%A _N. J. A. Sloane_, Dec 17 2013
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