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Search: id:A058844
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| A058844 |
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Number of ways of placing n labeled balls into 4 indistinguishable boxes with at least 2 balls in each box. |
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+0
4
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| 105, 1260, 9450, 56980, 302995, 1487200, 6914908, 30950920, 134779645, 575156036, 2417578670, 10046531276, 41388056231, 169371383384, 689568172832, 2796362035104, 11305163394129, 45595968007260
(list; graph; listen)
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OFFSET
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8,1
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LINKS
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T. D. Noe, Table of n, a(n) for n=8..200
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FORMULA
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E.g.f.: ((exp(x) - 1 - x)^4)/4!. G.f.: x^8*(288*x^6 - 1560*x^5 + 3500*x^4 - 4130*x^3 + 2625*x^2 - 840*x + 105)/ ((1 - x)^4*(1 - 2*x)^3*(1 - 3*x)^2*(1 - 4*x))
a(n) = [4^n-3^(n-1)(4n+12)+2^(n-1)(12+9n+3n^2)-4n^3-8n-4]/24. - David Wasserman (dwasserm(AT)earthlink.net), Jun 06 2007
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EXAMPLE
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a(8)=8!/(2!*2!*2!*2!*4!)=105
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CROSSREFS
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Cf. A000247 (2 boxes), A000478 (3 boxes).
Sequence in context: A166816 A166798 A033593 this_sequence A165382 A051015 A076377
Adjacent sequences: A058841 A058842 A058843 this_sequence A058845 A058846 A058847
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KEYWORD
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easy,nonn
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AUTHOR
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Michael Steyer (msteyer(AT)osram.de), Dec 02 2000
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EXTENSIONS
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More terms from James A. Sellers (sellersj(AT)math.psu.edu), Dec 06 2000
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