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A054252 Triangle T(n,k) of n X n binary matrices with k=0..n^2 ones under action of dihedral group of the square D_4. 8
1, 1, 1, 1, 1, 2, 1, 1, 1, 3, 8, 16, 23, 23, 16, 8, 3, 1, 1, 3, 21, 77, 252, 567, 1051, 1465, 1674, 1465, 1051, 567, 252, 77, 21, 3, 1, 1, 6, 49, 319, 1666, 6814, 22475, 60645, 136080, 256585, 410170, 559014, 652048, 652048, 559014, 410170, 256585, 136080 (list; graph; refs; listen; history; internal format)
OFFSET

0,6

EXAMPLE

[1], [1, 1], [1, 1, 2, 1, 1], [1, 3, 8, 16, 23, 23, 16, 8, 3, 1], ...

There are 8 nonisomorphic 3 X 3 binary matrices with two ones under action of D_4:

[0 0 0] [0 0 0] [0 0 0] [0 0 0] [0 0 0] [0 0 0] [0 0 0] [0 0 1]

[0 0 0] [0 0 0] [0 0 1] [0 0 1] [0 1 0] [0 1 0] [1 0 1] [0 0 0]

[0 1 1] [1 0 1] [0 1 0] [1 0 0] [0 0 1] [0 1 0] [0 0 0] [1 0 0].

CROSSREFS

Cf. A019318, A014409.

Sequence in context: A201949 A112707 A196017 * A007442 A054772 A085384

Adjacent sequences:  A054249 A054250 A054251 * A054253 A054254 A054255

KEYWORD

easy,nonn,tabf

AUTHOR

Vladeta Jovovic (vladeta(AT)eunet.rs), May 04 2000

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Last modified February 15 05:45 EST 2012. Contains 205694 sequences.