A103641 Number of tilings of the Aztec dungeon D_n.

1, 2, 13, 2197, 742586, 815730721, 23298085122481, 1330833218366359682, 247064529073450392704413, 1192533292512492016559195008117, 11512260858197858155912142995868417306

Offset

0,2

Links

Table of n, a(n) for n=0..10.

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

Formula

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

Prog

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

Crossrefs

Sequence in context: A004071 A174363 A158026 * A144983 A110820 A139519

Adjacent sequences: A103638 A103639 A103640 * A103642 A103643 A103644

Keyword

nonn

Author

Ralf Stephan, Feb 19 2005

Status

approved