This site is supported by donations to The OEIS Foundation.



Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A045310 Number of matchings in n-cube. 4
1, 2, 7, 108, 41025, 13803794944, 7174574164703330195841 (list; graph; refs; listen; history; text; internal format)



a(4) = A033532(1), a(5) = A033532(2).

a(3) = A033516(2) = A033535(2). - Alois P. Heinz, Dec 09 2013

Equivalently, the number of decompositions of an n-dimensional cube of size 2 into (zero or more) unit cubes (1 X 1 X ... X 1) and "dominoes" (2 X 1 X 1 X ... X 1). - Hugo van der Sanden, Nov 30 2016


Table of n, a(n) for n=0..6.

Per Hakan Lundow, Computation of matching polynomials and the number of 1-factors in polygraphs, Research report, No 12, 1996, Department of Math., Umea University, Sweden.

Per Hakan Lundow, Enumeration of matchings in polygraphs, 1998.

Per Hakan Lundow, GrafPack (Mathematica package).

Hugo van der Sanden, find2: Proof of concept in perl

Hugo van der Sanden, find2c.c: Fast version in C.

Eric Weisstein's World of Mathematics, Hypercube Graph

Eric Weisstein's World of Mathematics, Independent Edge Set

Eric Weisstein's World of Mathematics, Matching


From Max Alekseyev, Nov 16 2009: (Start)

E.g., for n=2, we have

1 matching of size 0 (i.e., the empty matching)

4 matchings of size 1 (i.e., an edge)

2 matchings of size 2 (that are the perfect matchings).

So a(2) = 1 + 4 + 2 = 7, whereas A005271(2) = 2. (End)


For Perl and C programs see Links section.


For perfect matchings see A005271.

For matching polynomials, see A192437, A302235.

Cf. A033532.

Sequence in context: A162634 A235470 A072664 * A224445 A000157 A264999

Adjacent sequences:  A045307 A045308 A045309 * A045311 A045312 A045313




Per H. Lundow



Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 9 08:20 EST 2019. Contains 329877 sequences. (Running on oeis4.)