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Search: id:A115403
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| A115403 |
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Numbers n such that n^3+1 is 3-almost prime (product of three primes). |
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3
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| 3, 9, 10, 12, 13, 21, 25, 30, 34, 36, 40, 46, 52, 66, 76, 81, 90, 96, 118, 120, 126, 130, 132, 142, 144, 154, 165, 168, 172, 177, 180, 193, 196, 198, 204, 216, 226, 228, 238, 240, 246, 250, 256, 262, 268, 273, 282, 288, 294, 312, 333, 336, 345, 346, 366, 370
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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It appears that there is only one known example of three consecutive primes p, q, r whose product is 1 more than a perfect cube, namely 7*11*13 = 1001, and that probably no other examples exist. - njas, Apr 27 2008
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FORMULA
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n^3+1=p*q*r where p, q, r are primes (not necessarily distinct).
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EXAMPLE
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9 is a member because 3^9+1=730=2*5*73 (product of three primes).
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CROSSREFS
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Cf. A014612 = 3-almost primes.
Sequence in context: A043048 A024574 A119203 this_sequence A059012 A055063 A030354
Adjacent sequences: A115400 A115401 A115402 this_sequence A115404 A115405 A115406
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KEYWORD
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nonn
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AUTHOR
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Zak Seidov (zakseidov(AT)yahoo.com), Mar 08 2006
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