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 A193153 Numbers of spanning trees of the (n,n)-torus grid graphs. 1
 1296, 82944, 9150625, 1575296100, 391476713761, 132821015040000, 59042071787233536, 33317165538875522500, 23276866101199344597601, 19729668557004748392960000, 19950922411933407541569256321, 23731310247317631978185581240644 (list; graph; refs; listen; history; text; internal format)
 OFFSET 3,1 COMMENTS Torus grid graphs are defined for n>=3. LINKS Alois P. Heinz, Table of n, a(n) for n = 3..80 Eric Weisstein's World of Mathematics, Spanning Tree Eric Weisstein's World of Mathematics, Torus Grid Graph MAPLE with (LinearAlgebra): a:= proc(n) local h, i, M;       M:= Matrix (2*n, shape=symmetric);       for h in [seq (seq ([i, j+n], j=1..n), i=1..n),                 seq ([[i, 1+(i mod n)], [n+i, n+1+(i mod n)]][], i=1..n)]       do M[h[]]:= -1 od;       for i to 2*n do M[i, i]:= -add (M[i, j], j=1..2*n) od;       Determinant (DeleteColumn (DeleteRow (M, 1), 1))     end: seq (a(n), n=3..20);  # Alois P. Heinz, Jul 17 2011 CROSSREFS Sequence in context: A017236 A017344 A223689 * A223273 A017464 A017596 Adjacent sequences:  A193150 A193151 A193152 * A193154 A193155 A193156 KEYWORD nonn AUTHOR Eric W. Weisstein, Jul 16 2011 STATUS approved

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