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A138207
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a(n) is the first term in a chain of at least n consecutive numbers each with exactly 7 distinct prime factors.
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4
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OFFSET
| 1,1
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COMMENTS
| a(5) > 10^13.
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REFERENCES
| Roger B. Eggleton and James A. MacDougall, Consecutive integers with equally many principal divisors, Math. Mag. 81 (2008), 235-248. [From T. D. Noe (noe(AT)sspectra.com), Oct 13 2008]
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CROSSREFS
| Cf. A087977, A087978, A138206, A154573.
Sequence in context: A147574 A046325 A136352 * A205291 A205899 A068816
Adjacent sequences: A138204 A138205 A138206 * A138208 A138209 A138210
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KEYWORD
| nonn
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AUTHOR
| Donovan Johnson (donovan.johnson(AT)yahoo.com), Mar 06 2008
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EXTENSIONS
| a(4) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Jan 15 2009
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