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 A099390 Array T(m,n) read by antidiagonals: number of domino tilings (or dimer tilings) of the m X n grid (or m X n rectangle), for m>=1, n>=1. 42
 0, 1, 1, 0, 2, 0, 1, 3, 3, 1, 0, 5, 0, 5, 0, 1, 8, 11, 11, 8, 1, 0, 13, 0, 36, 0, 13, 0, 1, 21, 41, 95, 95, 41, 21, 1, 0, 34, 0, 281, 0, 281, 0, 34, 0, 1, 55, 153, 781, 1183, 1183, 781, 153, 55, 1, 0, 89, 0, 2245, 0, 6728, 0, 2245, 0, 89, 0, 1, 144, 571, 6336, 14824, 31529, 31529, 14824, 6336, 571, 144, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 COMMENTS There are many versions of this array (or triangle) in the OEIS. This is the main entry, which ideally collects together all the references to the literature and to other versions in the OEIS. But see A004003 for further information. - N. J. A. Sloane, Mar 14 2015 REFERENCES S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 406-412. P. E. John, H. Sachs, and H. Zernitz, Problem 5. Domino covers in square chessboards, Zastosowania Matematyki (Applicationes Mathematicae) XIX 3{4 (1987), 635{641. R. P. Stanley, Enumerative Combinatorics, Vol. 1, Cambridge University Press, 2nd ed., pp. 547 and 570. Darko Veljan, Kombinatorika: s teorijom grafova (Croatian) (Combinatorics with Graph Theory) mentions the value 12988816 = 2^4*901^2 for the 8 X 8 case on page 4. LINKS Alois P. Heinz, Table of n, a(n) for n = 1..1035 M. Aanjaneya and S. P. Pal, Faultfree tromino tilings of rectangles, arXiv:math/0610925 [math.CO], 2006. F. Ardila and R. P. Stanley, Tilings, arXiv:math/0501170 [math.CO], 2005. M. Ciucu, Enumeration of perfect matchings in graphs with reflective symmetry, Journal of Combinatorial Theory, Series A, Volume 77, Issue 1, January 1997, Pages 67-97. H. Cohn, 2-adic behavior of numbers of domino tilings, arXiv:math/0008222 [math.CO], 2000. Henry Cohn, 2-adic behavior of numbers of domino tilings, Electronic Journal of Combinatorics, 6 (1999), #R14. F. Faase, Results from the counting program Steven R. Finch, The Dimer Problem [From Steven Finch, Apr 20 2019] S. R. Finch, Two Dimensional Monomer Dimer Constant [Broken link] M. E. Fisher, Statistical mechanics of dimers on a plane lattice, Physical Review, 124 (1961), 1664-1672. P. Flajolet and R. Sedgewick, Analytic Combinatorics, 2009; see page 363. Laura Florescu, Daniela Morar, David Perkinson, Nicholas Salter, Tianyuan Xu, Sandpiles and Dominos, Electronic Journal of Combinatorics, Volume 22(1), 2015. W. Jockusch, Perfect matchings and perfect squares J. Combin. Theory Ser. A 67 (1994), no. 1, 100-115. P. E. John and H. Sachs, On a strange observation in the theory of the dimer problem, arXiv:math/9801094 [math.CO], 1998. Peter E. John and Horst Sachs, On a strange observation in the theory of the dimer problem, Discrete Math. 216 (2000), no. 1-3, 211-219. Per Hakan Lundow, Enumeration of matchings in polygraphs, 1998. P. W. Kasteleyn, The statistics of dimers on a lattice, I. the number of dimer arrangements on a quadratic lattice, Physica 27 (1961), 1209-1225. L. Pachter, Combinatorial approaches and conjectures for 2-divisibility problems concerning domino tilings of polyominoes, Electronic Journal of Combinatorics 4 (1997), #R29. J. Propp, Dimers and Dominoes J. Propp, Enumeration of Matchings: Problems and Progress, arXiv:math/9904150v2 [math.CO], 1999. Jaime Rangel-Mondragon, Polyominoes and Related Families, The Mathematica Journal, 9:3 (2005), 609-640. R. C. Read, A Note on Tiling Rectangles with Dominoes, The Fibonacci Quarterly, 18.1 (1980), 24-27. R. P. Stanley, A combinatorial miscellany H. N. V. Temperley and Michael E. Fisher, Dimer problem in statistical mechanics — an exact result, Philos. Mag. (8) 6 (1961), 1061-1063. Herman Tulleken, Polyominoes 2.2: How they fit together, (2019). Eric Weisstein's World of Mathematics, Domino Tiling Eric Weisstein, Illustration for T(4,4) = 36, from Domino Tilings web page (see previous link) [Included with permission] FORMULA If m, n even then T(m, n) = Prod(j=1..m/2, Prod(k=1..n/2, 4*cos(j*Pi/(m+1))^2 + 4*cos(k*Pi/(n+1))^2)). EXAMPLE 0,  1,  0,   1,    0,    1, ... 1,  2,  3,   5,    8,   13, ... 0,  3,  0,  11,    0,   41, ... 1,  5, 11,  36,   95,  281, ... 0,  8,  0,  95,    0, 1183, ... 1, 13, 41, 281, 1183, 6728, ... MAPLE (Maple code for the even-numbered rows from N. J. A. Sloane, Mar 15 2015. This is not totally satisfactory since it uses floating point. However, it is useful for getting the initial values quickly.) Digits:=100; p:=evalf(Pi); z:=proc(h, d) global p; evalf(cos( h*p/(2*d+1) )); end; T:=proc(m, n) global z; round(mul( mul( 4*z(h, m)^2+4*z(k, n)^2, k=1..n), h=1..m)); end; [seq(T(1, n), n=0..10)]; # A001519 [seq(T(2, n), n=0..10)]; # A188899 [seq(T(3, n), n=0..10)]; # A256044 [seq(T(n, n), n=0..10)]; # A004003 MATHEMATICA t[m_, n_] := Product[2*(2 + Cos[2j*Pi/(m+1)] + Cos[2k*Pi/(n+1)]), {k, 1, n/2}, {j, 1, m/2}]; t[_?OddQ, _?OddQ] = 0; Flatten[ Table[ FullSimplify[ t[m-n+1, n]], {m, 1, 12}, {n, 1, m}]](* Jean-François Alcover, Nov 25 2011 *) PROG (PARI) {T(n, k) = sqrtint(abs(polresultant(polchebyshev(n, 2, x/2), polchebyshev(k, 2, I*x/2))))} \\ Seiichi Manyama, Apr 13 2020 CROSSREFS See A187596 for another version (with m >= 0, n >= 0). See A187616 for a triangular version. See also A187617, A187618. See also A004003 for more literature on the dimer problem. Rows 2-13, 16 (without zeros) are A000045, A001835, A005178, A003775, A028468, A028469, A028470, A028471, A028472, A028473, A028474, A241908, A340532. Main diagonal is A004003. Cf. A103997, A103999, A233320, A230031, A233427. Sequence in context: A323073 A167279 A068920 * A297477 A124031 A289229 Adjacent sequences:  A099387 A099388 A099389 * A099391 A099392 A099393 KEYWORD tabl,nonn,changed AUTHOR Ralf Stephan, Oct 16 2004 EXTENSIONS Corrected broken URL's. - R. J. Mathar, Jan 06 2009 Fixed old link and added link to results page. - Frans J. Faase, Feb 04 2009 Entry edited by N. J. A. Sloane, Mar 15 2015 STATUS approved

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Last modified January 26 03:34 EST 2021. Contains 340429 sequences. (Running on oeis4.)