A103642 Number of tilings of the Aztec dungeon E_n.

1, 26, 2197, 371293, 1631461442, 23298085122481, 665416609183179841, 494129058146900785408826, 1192533292512492016559195008117, 5756130429098929077956071497934208653

Offset

0,2

Links

Table of n, a(n) for n=0..9.

M. Ciucu, Perfect matchings and perfect powers, arXiv:math/0501521 [math.CO], 2005.

Formula

Recurrence: a(n+6) = 13^(4n+16)*a(n), starting with 1, 2*13, 13^3, 13^5, 2*13^8, 13^12.

Prog

(PARI) a(n)=if(n<1, n==0, if(n<6, [2*13, 13^3, 13^5, 2*13^8, 13^12][n], 13^(4*n-8)*a(n-6)))

Crossrefs

Sequence in context: A268089 A173949 A266030 * A363990 A201623 A087616

Adjacent sequences: A103639 A103640 A103641 * A103643 A103644 A103645

Keyword

nonn

Author

Ralf Stephan, Feb 19 2005

Status

approved