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A168629 Numbers n such that n,n+1 and sum of this two numbers have 3 distinct prime factors. 1
1105, 1130, 1462, 1644, 1742, 1767, 2014, 2222, 2232, 2260, 2337, 2365, 2397, 2464, 2541, 2667, 2684, 2697, 2702, 2755, 2821, 2914, 3074, 3115, 3195, 3289, 3332, 3477, 3484, 3514, 3552, 3619, 3657, 3685, 3782, 3783, 3842, 3965, 4014, 4088, 4122, 4147 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..42.

EXAMPLE

FactorInteger[1105]=5*13*17, FactorInteger[1106]=2*7*79, FactorInteger[1105+1106]=3*11*67,..

MATHEMATICA

f[n_]:=Length[FactorInteger[n]]; lst={}; Do[If[f[n]>=3&&f[n+1]>=3&&f[n+n+1]>=3, AppendTo[lst, n]], {n, 8!}]; lst

CROSSREFS

Cf. A140077, A140078, A168626, A168628

Sequence in context: A022055 A008688 A107519 * A175521 A214607 A257759

Adjacent sequences:  A168626 A168627 A168628 * A168630 A168631 A168632

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Dec 01 2009

STATUS

approved

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Last modified March 28 05:07 EDT 2017. Contains 284182 sequences.