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A098027
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Smallest prime p such that p+2 is a product of exactly n distinct primes.
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0
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3, 13, 103, 1153, 15013, 255253, 4849843, 111546433, 4360010653, 100280245063, 5245694198743, 152125131763603, 7149881192889433, 421842990380476663, 16294579238595022363, 1106494163767990292293, 74135108972455349583763
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| In most cases a(n) = pn! - 2, where pn! is "factorial of odd primes": from 3 to n-th odd prime. - Zak Seidov - Zak Seidov (zakseidov(AT)yahoo.com) and Don Reble (djr(AT)nk.ca), Mar 10 2006
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EXAMPLE
| 3+2=5 (1 prime), 13+2=15=3*5 (2 primes), 103+2=105=3*5*7 (3 primes), ...
1153 is the 4-th entry in the sequence because it is followed by primes 1783, 1993, 2143, 2803, ... with the property 1153+2 = 3*5*7*11, 1783+2 = 3*5*7*17, 1993+2 = 3*5*7*19, 2143+2 = 3*5*11*13, 2803+2 = 3*5*11*17, ...
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CROSSREFS
| Cf. A067024 [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 02 2008]
Sequence in context: A168417 A127004 A068168 * A073587 A061377 A183604
Adjacent sequences: A098024 A098025 A098026 * A098028 A098029 A098030
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KEYWORD
| nonn
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AUTHOR
| Lekraj Beedassy (blekraj(AT)yahoo.com), Sep 10 2004
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EXTENSIONS
| Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Sep 18 2004
More terms from Zak Seidov (zakseidov(AT)yahoo.com) and Don Reble (djr(AT)nk.ca), Mar 10 2006
Corrected by Don Reble (djr(AT)nk.ca), Apr 03 2006
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