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A157486
Numbers n such that n-+1 are divisible by exactly 6 primes, counted with multiplicity.
3
1889, 3079, 4591, 5023, 6175, 6641, 7649, 9881, 10961, 11501, 11935, 12689, 13751, 14417, 15499, 15713, 16687, 18017, 18089, 18271, 19169, 19249, 19889, 19951
OFFSET
1,1
LINKS
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
KEYWORD
nonn
AUTHOR
STATUS
approved