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A232997 Number of tilings of a fortress (or Penta-Aztec-Diamond) of order n. 0
1, 1, 5, 50, 625, 15625, 1953125, 488281250, 152587890625, 95367431640625, 298023223876953125, 1862645149230957031250, 14551915228366851806640625, 227373675443232059478759765625, 17763568394002504646778106689453125, 2775557561562891351059079170227050781250 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

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).

LINKS

Table of n, a(n) for n=0..15.

Tri Lai, New aspects of regions whose tilings are enumerated by perfect powers, Electronic Journal of Combinatorics, 20(4), 2013, #P31. See Th. 8.

MAPLE

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;

[seq(f(n), n=0..30)];

CROSSREFS

Sequence in context: A233068 A237020 A156058 * A234464 A047736 A185272

Adjacent sequences:  A232994 A232995 A232996 * A232998 A232999 A233000

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Dec 17 2013

STATUS

approved

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Last modified June 18 19:04 EDT 2021. Contains 345120 sequences. (Running on oeis4.)