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Search: id:A032180
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| A032180 |
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Number of ways to partition n labeled elements into 6 pie slices. |
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+0
1
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| 120, 2520, 31920, 317520, 2739240, 21538440, 158838240, 1118557440, 7612364760, 50483192760, 328191186960, 2100689987760, 13282470124680, 83169792213480, 516729467446080, 3190281535536480
(list; graph; listen)
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OFFSET
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6,1
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COMMENT
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For n>=6, a(n) is equal to the number of functions f: {1,2,...,n-1}->{1,2,3,4,5,6} such that Im(f) contains 5 fixed elements. - Aleksandar M. Janjic and Milan R. Janjic (agnus(AT)blic.net), Feb 27 2007
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LINKS
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Milan Janjic, Enumerative Formulas for Some Functions on Finite Sets
C. G. Bower, Transforms (2)
Index entries for sequences related to necklaces
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FORMULA
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"CIJ[ 6 ]" (necklace, indistinct, labeled, 6 parts) transform of 1, 1, 1, 1...
120*S(n, 6).
a(n)= 5*2^(n-1)-10*3^(n-1)+10*4^(n-1)-5^n+6^(n-1)-1. a(n)=120*A000770(n). - Emeric Deutsch (deutsch(AT)duke.poly.edu), May 02 2004
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MAPLE
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with (combstruct):ZL:=[S, {S=Sequence(U, card=r), U=Set(Z, card>=1)}, labeled]: seq(count(subs(r=6, ZL), size=m)/6, m=6..21); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 08 2008
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CROSSREFS
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Cf. A000770, A008277.
Sequence in context: A056286 A166779 A038745 this_sequence A000553 A126232 A105943
Adjacent sequences: A032177 A032178 A032179 this_sequence A032181 A032182 A032183
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KEYWORD
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nonn,easy
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AUTHOR
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Christian G. Bower (bowerc(AT)usa.net)
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