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A101934 Numbers n with omega(n) smaller than omega(n-1) and omega(n+1). 3
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..1000

EXAMPLE

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).

MATHEMATICA

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-Fran├žois Alcover, Nov 14 2016 *)

CROSSREFS

Cf. A001221, A101932, A076763.

Sequence in context: A057891 A164708 A030792 * A164861 A040150 A214629

Adjacent sequences:  A101931 A101932 A101933 * A101935 A101936 A101937

KEYWORD

easy,nonn

AUTHOR

Neil Fernandez, Dec 21 2004

STATUS

approved

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Last modified January 29 04:57 EST 2020. Contains 331335 sequences. (Running on oeis4.)