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A101934
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Numbers n with omega(n) smaller than omega(n-1) and omega(n+1).
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3
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11, 13, 19, 23, 25, 27, 29, 37, 41, 43, 47, 49, 53, 59, 61, 64, 67, 71, 73, 79, 81, 83, 89, 97, 101, 103, 107, 109, 113, 121, 125, 131, 137, 139, 149, 151, 155, 157, 163, 167, 169, 173, 179, 181, 191, 193, 197, 199, 211, 221, 223, 227
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OFFSET
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1,1
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LINKS
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EXAMPLE
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125 is in the sequence because it has one unique prime factor (5), which is fewer than its neighbors 124 (two such factors, namely 2 and 31) and 126 (two such factors, namely 2 and 53).
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MATHEMATICA
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For[i=2, i<1000, If[And[Length[FactorInteger[i 1]]>Length[FactorInteger[i]], Length[FactorInteger[i+1]] > Length[FactorInteger[i]]], Print[i]]; i++ ]
(* Second program: *)
Select[Range[1000], PrimeNu[#] < Min[PrimeNu[#-1], PrimeNu[#+1]]&] (* Jean-François Alcover, Nov 14 2016 *)
Flatten[Position[Partition[PrimeNu[Range[250]], 3, 1], _?(#[[1]]>#[[2]]<#[[3]]&), 1, Heads->False]]+1 (* Harvey P. Dale, Apr 18 2021 *)
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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