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A052281
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Number of 4 X 4 symmetric stochastic matrices under row and column permutations.
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3
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1, 1, 3, 6, 16, 29, 62, 107, 195, 320, 522, 804, 1234, 1804, 2626, 3700, 5155, 7038
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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EXAMPLE
| There are 6 nonisomorphic symmetric 4 X 4 matrices with row and column sums 3:
[0 0 0 3] [0 0 1 2] [0 0 1 2] [0 0 1 2] [0 0 1 2] [0 1 1 1]
[0 0 3 0] [0 0 2 1] [0 1 1 1] [0 1 2 0] [0 2 1 0] [1 0 1 1]
[0 3 0 0] [1 2 0 0] [1 1 1 0] [1 2 0 0] [1 1 0 1] [1 1 0 1]
[3 0 0 0] [2 1 0 0] [2 1 0 0] [2 0 0 1] [2 0 1 0] [1 1 1 0]
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CROSSREFS
| Cf. A053493, A001496, A052280, A052282.
Sequence in context: A130596 A151954 A032247 * A196261 A122742 A052370
Adjacent sequences: A052278 A052279 A052280 * A052282 A052283 A052284
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KEYWORD
| more,nonn
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AUTHOR
| Vladeta Jovovic (vladeta(AT)eunet.rs), Feb 06 2000
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