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Search: id:A101294
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| A101294 |
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Numbers n such that omega(n-2) = omega(n-1) = omega(n) = omega(n+1) = omega(n+2). |
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+0
2
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| 56, 93, 94, 117, 143, 144, 145, 146, 160, 207, 214, 215, 216, 217, 297, 303, 325, 326, 327, 393, 537, 687, 723, 801, 1137, 1347, 1467, 1537, 1713, 1943, 1983, 2103, 2217, 2304, 2305, 2306, 2427, 2643, 2666, 2716, 3867, 3914, 4413
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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143 is in the sequence because it has two unique prime factors (11 and 13), the same number as its two nearest neighbors on both sides (141 has 3 and 47, 142 has 2 and 71, 144 has 2 and 3, and 145 has 5 and 29).
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MATHEMATICA
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For[i=2, i<10000, If[And[Length[FactorInteger[i-2]]==Length[FactorInteger[i]], Length[FactorInteger[i-1]]==Length[FactorInteger[i]], Length[FactorInteger[i+1]]==Length[FactorInteger[i]], Length[FactorInteger[i+2]]==Length[FactorInteger[i]]], Print[i]]; i++ ]
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CROSSREFS
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Cf. A001221, A101932.
Sequence in context: A043938 A104394 A101935 this_sequence A039534 A063347 A054891
Adjacent sequences: A101291 A101292 A101293 this_sequence A101295 A101296 A101297
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KEYWORD
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easy,nonn
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AUTHOR
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N. Fernandez (primeness(AT)borve.org), Dec 21 2004
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EXTENSIONS
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Edited by njas, Mar 17 2007
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