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Search: id:A052215
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| A052215 |
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a(n) = smallest number m such that m and m+1 are the product of exactly n distinct primes. |
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+0
7
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| 2, 14, 230, 7314, 378014, 11243154, 965009045, 65893166030, 5702759516090, 605247139068494, 78971815814237709
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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2^63 < a(12) <= 22593106657425552170. [From Donovan Johnson (donovan.johnson(AT)yahoo.com), Oct 23 2008]
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EXAMPLE
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14 and 15 are both the product of 2 primes
230 is the 3rd entry because we have (230=2*5*23, 231=3*7*11).
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CROSSREFS
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Cf. A093548, A093549, A093550, A115186.
Sequence in context: A118086 A048163 A093548 this_sequence A053846 A053855 A152476
Adjacent sequences: A052212 A052213 A052214 this_sequence A052216 A052217 A052218
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KEYWORD
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hard,nice,nonn
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AUTHOR
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Erich Friedman (efriedma(AT)stetson.edu), Jan 29 2000
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EXTENSIONS
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More terms from Naohiro Nomoto (6284968128(AT)geocities.co.jp), Jul 08 2001
a(7) from Farideh Firoozbakht (mymontain(AT)yahoo.com), Apr 06 2004
a(8)-a(10) from Martin Fuller (martin_n_fuller(AT)btinternet.com), Jan 17 2006
a(11) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Oct 23 2008
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