

A168628


Numbers n such that n and n+1 have 4 distinct prime factors.


2



37961, 44485, 45695, 50141, 51429, 55131, 55385, 61335, 63365, 64295, 67165, 68265, 68475, 70005, 70091, 71709, 72709, 76153, 80445, 81549, 81719, 82041, 84435, 85491, 86241, 90364, 95381, 97383, 98021, 99085, 99385, 99429, 99789, 100165, 100491, 100595
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..36.


MATHEMATICA

f[n_]:=Length[FactorInteger[n]]; lst={}; Do[If[f[n]>=4&&f[n1]>=4&&f[n+1]>=4, AppendTo[lst, n]], {n, 9!}]; lst
SequencePosition[PrimeNu[Range[110000]], {4, 4, 4}][[All, 1]]+1 (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Apr 27 2018 *)


CROSSREFS

Cf. A140077, A140078, A168626
Sequence in context: A102332 A172425 A224906 * A178286 A187938 A235185
Adjacent sequences: A168625 A168626 A168627 * A168629 A168630 A168631


KEYWORD

nonn


AUTHOR

Vladimir Joseph Stephan Orlovsky, Dec 01 2009


EXTENSIONS

Corrected and extended by Harvey P. Dale, Apr 27 2018


STATUS

approved



