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Search: id:A133360
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| A133360 |
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Number of surjections from an n-element set to a nine-element set. |
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+0
2
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OFFSET
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9,1
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FORMULA
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a(n)=sum((-1)^(9-k)*C(9,k)*k^n) with n>=9 and k=9,8,...,1.
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CROSSREFS
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Cf. A000918, A000919, A000920, A001117, A001118, A135456.
Sequence in context: A045511 A029577 A133082 this_sequence A071551 A125001 A017537
Adjacent sequences: A133357 A133358 A133359 this_sequence A133361 A133362 A133363
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KEYWORD
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nonn
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AUTHOR
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Mohamed Bouhamida (bhmd95(AT)yahoo.fr), Dec 21 2007
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