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Search: id:A114869
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| A114869 |
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Floor[n^(n/5)/n!!!!! ]. |
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+0
1
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| 1, 0, 0, 0, 1, 1, 1, 1, 1, 2, 2, 2, 2, 3, 6, 5, 5, 7, 10, 16, 12, 14, 18, 26, 39, 31, 35, 45, 64, 98, 79, 88, 114, 163
(list; graph; listen)
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OFFSET
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1,10
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COMMENT
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This sequence is an approximation of a quintuple factorial analogue to Stirling's approximation to factorial. Note that a(n) is exact for n = 1, 5, 10.
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FORMULA
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a(n) = Floor[n^(n/5)/n!!! ]. a(n) = Floor[5thRoot(A000312(n))/A085157(n)].
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EXAMPLE
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a(10) = Floor[10^2/10!!!!! ] = Floor[10^2/50] = Floor[2] = 2.
a(15) = Floor[15^3/15!!!!! ] = Floor[(15^3)/750] = Floor[4.5] = 4.
a(20) = Floor[20^4/20!!!!! ] = Floor[(20^4)/15000] = Floor[10.6666667] = 10.
a(25) = Floor[25^5/25!!!!! ] = Floor[(25^5)/375000] = Floor[26.0416667] = 26.
a(30) = Floor[30^6/30!!!!! ] = Floor[(30^6)/11250000] = Floor[64.8] = 64.
a(35) = Floor[35^7/35!!!!! ] = Floor[(35^7)/393750000] = Floor[163.401389] = 163.
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CROSSREFS
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Cf. A000312, A006882, A055775, A085157.
Sequence in context: A098133 A138185 A138705 this_sequence A078228 A119762 A125914
Adjacent sequences: A114866 A114867 A114868 this_sequence A114870 A114871 A114872
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KEYWORD
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easy,nonn
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AUTHOR
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Jonathan Vos Post (jvospost3(AT)gmail.com), Feb 20 2006
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