login
This site is supported by donations to The OEIS Foundation.
Logo

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A091472 Number of n X n matrices with entries {0,1} that are diagonalizable over the complex numbers. 2
2, 12, 320, 43892 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

A matrix M is diagonalizable over a field F if there is an invertible matrix S with entries from F such that S^(-1) M S is diagonal.

An n X n matrix M is diagonalizable if and only if it has n linearly independent eigenvectors.

REFERENCES

R. A. Horn and C. R. Johnson, Matrix Analysis, Cambridge, 1988, Section 1.3.

LINKS

Eric Weisstein's World of Mathematics, Diagonalizable Matrix

Index entries for sequences related to binary matrices

EXAMPLE

a(2) = 12: all except 00/10, 01/00, 11/01, 10/11.

MATHEMATICA

Needs["Utilities`FilterOptions`"] Options[DiagonalizableQ]={ Field->Complexes, ZeroTest->(RootReduce[ # ]===0&) };

Matrices[n_, l_List:{0, 1}] := Partition[ #, n]&/@Flatten[Outer[List, Sequence@@Table[l, {n^2}]], n^2-1]

DiagonalizableQ[m_List?MatrixQ, opts___] := Module[ { field=Field/.{opts}/.Options[DiagonalizableQ], eigenopts=FilterOptions[Eigenvectors, opts] }, Switch[field, Complexes, ComplexDiagonalizableQ[m, eigenopts], Reals, RealDiagonalizableQ[m, eigenopts] ] ]

Table[Count[Matrices[n], _?DiagonalizableQ], {n, 4}]

CROSSREFS

Cf. A091470, A091471.

Sequence in context: A012422 A122767 A094047 * A156518 A012727 A181142

Adjacent sequences:  A091469 A091470 A091471 * A091473 A091474 A091475

KEYWORD

nonn,more

AUTHOR

Eric Weisstein (eric(AT)weisstein.com), Jan 12, 2004

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified February 14 11:36 EST 2012. Contains 205623 sequences.