OFFSET
0,2
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..400
N. Allegra, Exact solution of the 2d dimer model: Corner free energy, correlation functions and combinatorics, arXiv:1410.4131 [cond-mat.stat-mech], 2014. See Table 1.
Index entries for linear recurrences with constant coefficients, signature (11,-25,11,-1).
FORMULA
G.f.: (1-x)*(x^2-5*x+1)/(x^4-11*x^3+25*x^2-11*x+1). - Alois P. Heinz, Oct 28 2012
MAPLE
ft:=(m, n)->
2^(m*n/2)*mul( mul(
(cos(Pi*i/(n+1))^2+cos(Pi*j/(m+1))^2), j=1..m/2), i=1..n/2);
gt:=(m, n)->round(evalf(ft(m, n), 300));
tt:=[seq(gt(4, 2*n), n=0..10)];
# second Maple program:
a:= n-> (<<0|1|0|0>, <0|0|1|0>, <0|0|0|1>, <-1|11|-25|11>>^n.
<<1, 5, 36, 281>>)[1, 1]:
seq(a(n), n=0..30); # Alois P. Heinz, Oct 28 2012
MATHEMATICA
LinearRecurrence[{11, -25, 11, -1}, {1, 5, 36, 281}, 25] (* Jean-François Alcover, Jun 17 2018 *)
PROG
(PARI) x='x+O('x^200); Vec((1-x)*(x^2-5*x+1)/(x^4-11*x^3+25*x^2-11*x+1)) \\ Altug Alkan, Mar 23 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Apr 13 2011
STATUS
approved