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Search: id:A115186
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| A115186 |
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Smallest number m such that m and m+1 have exactly n prime factors (counted with multiplicity). |
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+0
5
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| 2, 9, 27, 135, 944, 5264, 29888, 50624, 203391, 3290624, 6082047, 32535999, 326481920, 3274208000, 6929459199, 72523096064, 37694578688
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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A001222(a(n)) = A001222(a(n)+1) = n: subsequence of A045920;
a(16) > 4*10^10 - Martin Fuller (martin_n_fuller(AT)btinternet.com), Jan 17 2006
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REFERENCES
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J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 135, p. 46, Ellipses, Paris 2008.
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EXAMPLE
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a(10) = 3290624 = 6427 * 2^9, 3290624+1 = 13 * 5^5 * 3^4:
A001222(13290624) = A001222(13290625) = 10.
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CROSSREFS
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Cf. A001222, A045920, A052215, A093548.
Sequence in context: A123904 A128239 A019065 this_sequence A090900 A100293 A001093
Adjacent sequences: A115183 A115184 A115185 this_sequence A115187 A115188 A115189
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jan 16 2006
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EXTENSIONS
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a(13)-a(15) from Martin Fuller (martin_n_fuller(AT)btinternet.com), Jan 17 2006
a(16), a(17) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Apr 08 2008
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