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Search: id:A074931
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| A074931 |
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2-almost-primes equidistant from consecutive prime twin pairs. |
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+0
1
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| 3, 5, 17, 29, 41, 71, 149, 281, 317, 347, 359, 397, 647, 751, 787, 857, 907, 1093, 1279, 1381, 1511, 1531, 1663, 1783, 2447, 2683, 2803, 3271, 3323, 4019, 4153, 4513, 4567, 4639, 5557, 5647, 5801, 5923, 6599, 6659, 6911, 7013, 7573, 7883, 9187, 9257, 9431
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OFFSET
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1,1
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COMMENT
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Numbers equidistant from consecutive twins (see A074953) are multiples of 3 and they may be almost primes only of form 3*prime. In the sequence, these primes are given. Also: A001748 (3*prime 2-almost-primes) and A001358 (all 2-almost-primes).
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EXAMPLE
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17 is OK because 3*17=51 is equidistant between {41,43} and {59,61}.
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CROSSREFS
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Cf. A001358, A001748, A074953.
Sequence in context: A079373 A038703 A163586 this_sequence A023226 A113169 A079496
Adjacent sequences: A074928 A074929 A074930 this_sequence A074932 A074933 A074934
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KEYWORD
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nonn
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AUTHOR
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N. Fernandez, Zak Seidov (primeness(AT)borve.org; zakseidov(AT)yahoo.com), Oct 10 2002
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