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A158458
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Numbers k such that k+ big-Omega(k) is prime.
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0
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2, 8, 9, 15, 20, 21, 28, 32, 35, 39, 44, 48, 50, 51, 57, 65, 68, 69, 70, 76, 77, 87, 95, 98, 108, 110, 111, 124, 129, 135, 148, 154, 155, 161, 162, 164, 168, 170, 176, 177, 188, 189, 190, 192, 209, 221, 225, 230, 236, 237, 238, 249, 252, 264, 266, 267, 268, 272, 290
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| 2 is the only prime number in the sequence [Michel Lagneau (mn.lagneau2(AT)orange.fr), May 17 2010]
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FORMULA
| {k: k+A001222(k) in A000040}.
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EXAMPLE
| a(2) = 8=2*2*2 and 8+3=11 is prime. a(3)=9=3*3 and 9+2=11 is prime. a(4)=15=3*5 and 15+2=17 is prime.
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MAPLE
| for k from 2 to 400 do if isprime(k+numtheory[bigomega](k)) then printf("%d, ", k) ; fi; od: [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 19 2009, May 23 2010]
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MATHEMATICA
| Select[Range[10^3], PrimeQ[ # + Plus @@ Last /@ FactorInteger[ # ]] &] (* Michel Lagneau (mn.lagneau2(AT)orange.fr), May 17 2010 *)
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CROSSREFS
| Cf. A000040, A001222.
Cf. A067532, A078762, A068080 [Michel Lagneau (mn.lagneau2(AT)orange.fr), May 17 2010]
Sequence in context: A073606 A047353 A032928 * A056805 A046679 A004999
Adjacent sequences: A158455 A158456 A158457 * A158459 A158460 A158461
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KEYWORD
| nonn
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AUTHOR
| Juri-Stepan Gerasimov (2stepan(AT)ramblet.ru), Mar 19 2009
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EXTENSIONS
| 191 replaced by 192 and extended by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 19 2009
Generalized by inserting a(1)=2. [Michel Lagneau (mn.lagneau2(AT)orange.fr), May 17 2010]
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