1,2

The matchings contain 2^n / 2 = 2^(n-1)) edges.

It appears that a(6) was first found by D. H. Wiedemann, unpublished.

M. K. Chari and M. Joswig, Complexes of discrete Morse functions, Disc. Math. 302 (2005), 39-51.

L. H. Clark, J. C. George and T. D. Porter, On the number of 1-factors in the n-cube, Congress. Numer., 127 (1997), 67-69.

N. Graham and F. Harary, The number of perfect matchings in a hypercube, Appl. Math. Lett., 1 (1988), 45-48.

Per Hakan Lundow, "Computation of matching polynomials and the number of 1-factors in polygraphs", Research reports, No 12, 1996, Department of Mathematics, Ume{\aa} University.

J. Propp, Enumeration of matchings: problems and progress, pp. 255-291 in L. J. Billera et al., eds, New Perspectives in Algebraic Combinatorics, Cambridge, 1999 (see Problem 18).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

J. Propp, Twenty open problems in enumeration of matchings.

J. Propp, Updated article

J. Propp, Enumeration of matchings: problems and progress, in L. J. Billera et al. (eds.), New Perspectives in Algebraic Combinatorics

Cf. A112311.

For all matchings see A045310.

Sequence in context: A122894 A042675 A015177 this_sequence A012938 A013093 A013169

Adjacent sequences: A005268 A005269 A005270 this_sequence A005272 A005273 A005274

nonn,hard,nice

N. J. A. Sloane (njas(AT)research.att.com).

n=6 term from Per Hakan Lundow (phl(AT)abel.math.umu.se) Jul 15 1996.