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Search: id:A113008
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| A113008 |
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Numbers n such that n, n+1, n+2, n+3 and n+4 are respectively 1,2,3,4,5-almost primes. |
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+0
2
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| 15121, 35521, 52321, 117841, 235441, 313561, 398821, 516421, 520021, 531121, 570601, 623641, 761113, 838561, 941041, 1117321, 1190821, 1317361, 1333621, 1336177, 1372081, 1413793, 1424041, 1431361, 1488901, 1513921, 1560121
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OFFSET
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1,1
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EXAMPLE
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15121 is prime (or 1-almost prime), 15122=2*7561 is semiprime (or 2-almost prime), 15123=3*71*71 is 3-almost prime, 15124=2*2*29*199 is 4-almost prime, 15125=5*5*5*11*11 is 5-almost prime.
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MATHEMATICA
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f[n_] := Plus @@ Last /@ FactorInteger@n; t = {}; Do[p = Prime[n]; If[Array[ f[p + # ] &, 4] == {2, 3, 4, 5}, AppendTo[t, p]], {n, 126483}]; t (* Robert G. Wilson v *)
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CROSSREFS
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Sequence in context: A147578 A151595 A124047 this_sequence A004935 A004955 A004975
Adjacent sequences: A113005 A113006 A113007 this_sequence A113009 A113010 A113011
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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), Jan 03 2006
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(at)rgwv.com), Jan 05 2006
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