A168628 - OEIS

A168628

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

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[n-1]>=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: A172425 A224906 A364309 * A178286 A187938 A235185

Adjacent sequences: A168625 A168626 A168627 * A168629 A168630 A168631