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A123544
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Number of connected labeled 2-regular relations of order n.
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3
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0, 0, 1, 6, 87, 1980, 66270, 3050460, 184716630, 14231775600, 1359481407480, 157694893448400, 21835679256606600, 3557942554594428000, 673941365091485290800, 146851484638349504613600
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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REFERENCES
| R. W. Robinson, Numerical implementation of graph counting algorithms, AGRC Grant, Math. Dept., Univ. Newcastle, Australia, 1982.
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LINKS
| R. W. Robinson, Table of n, a(n) for n = 0..48
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CROSSREFS
| Connected version of A001499.
Sequence in context: A047786 A181271 A113666 * A138216 A171207 A173224
Adjacent sequences: A123541 A123542 A123543 * A123545 A123546 A123547
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Nov 13 2006
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