A103641 - OEIS

%I #6 May 28 2019 19:33:12

%S 1,2,13,2197,742586,815730721,23298085122481,1330833218366359682,

%T 247064529073450392704413,1192533292512492016559195008117,

%U 11512260858197858155912142995868417306

%N Number of tilings of the Aztec dungeon D_n.

%H M. Ciucu, <a href="https://arxiv.org/abs/math/0501521">Perfect matchings and perfect powers</a>, arXiv:math/0501521 [math.CO], 2005.

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

%o (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)))

%K nonn

%O 0,2

%A _Ralf Stephan_, Feb 19 2005