OFFSET
1,1
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..10000
EXAMPLE
173 is in the sequence because it has one unique prime factor (itself), whereas
171, 172, 174 and 175 each have more.
MATHEMATICA
For[i=2, i<1000, 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++ ]
Select[Range[6500], PrimeNu[#] < Min[PrimeNu[# - 1], PrimeNu[# - 2], PrimeNu[# + 1], PrimeNu[# + 2]] &] (* G. C. Greubel, May 15 2017 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Neil Fernandez, Dec 21 2004
STATUS
approved