A157486 - OEIS

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A157486

Numbers n such that n-+1 are divisible by exactly 6 primes, counted with multiplicity.

1889, 3079, 4591, 5023, 6175, 6641, 7649, 9881, 10961, 11501, 11935, 12689, 13751, 14417, 15499, 15713, 16687, 18017, 18089, 18271, 19169, 19249, 19889, 19951

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OFFSET

1,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..4000

MATHEMATICA

q=6; lst={}; Do[If[Plus@@Last/@FactorInteger[n-1]==q&&Plus@@Last/@FactorInteger[n+1]==q, AppendTo[lst, n]], {n, 9!}]; lst

Mean/@SequencePosition[PrimeOmega[Range[20000]], {6, _, 6}] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Sep 23 2019 *)

CROSSREFS

Cf. A124936, A014612, A157483, A157484, A157485

Sequence in context: A237540 A206746 A106764 * A086476 A279621 A168226

Adjacent sequences: A157483 A157484 A157485 * A157487 A157488 A157489

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Mar 01 2009

STATUS

approved