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Search: id:A033306
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| A033306 |
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Triangle of coefficients of ordered cycle-index polynomials: T(n,k) = binomial(n,k)*Bell(k)*Bell(n-k). |
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+0
4
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| 1, 1, 1, 2, 2, 2, 5, 6, 6, 5, 15, 20, 24, 20, 15, 52, 75, 100, 100, 75, 52, 203, 312, 450, 500, 450, 312, 203, 877, 1421, 2184, 2625, 2625, 2184, 1421, 877, 4140, 7016, 11368, 14560, 15750, 14560, 11368, 7016, 4140, 21147, 37260, 63144, 85260, 98280, 98280
(list; table; graph; listen)
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OFFSET
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0,4
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REFERENCES
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J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 80.
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FORMULA
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E.g.f.: exp(exp(x*y)+exp(x)-2).
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EXAMPLE
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1; 1,1; 2,2,2; 5,6,6,5; 15,20,24,20,15; 52,75,100,100,75,5; ...
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CROSSREFS
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Cf. A000110, row sums give A001861.
Columns include A000110 and A052889.
Sequence in context: A066835 A123953 A097006 this_sequence A136347 A162145 A145876
Adjacent sequences: A033303 A033304 A033305 this_sequence A033307 A033308 A033309
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KEYWORD
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nonn,tabl,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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Edited by Vladeta Jovovic (vladeta(AT)eunet.rs), Sep 17 2003
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