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A086297
Squarefree kernels of 7-smooth numbers.
1
1, 2, 3, 2, 5, 6, 7, 2, 3, 10, 6, 14, 15, 2, 6, 10, 21, 6, 5, 3, 14, 30, 2, 35, 6, 10, 42, 15, 6, 7, 10, 6, 14, 30, 21, 2, 70, 6, 15, 10, 3, 42, 30, 6, 14, 10, 105, 6, 14, 30, 5, 42, 2, 15, 70, 6, 21, 30, 10, 6, 42, 35, 30, 21, 6, 14, 10, 210, 6, 14, 15, 30, 3, 35, 10, 42, 2
OFFSET
1,2
COMMENTS
a(n) = A007947(A002473(n));
a(n) <= 210 = 7*5*3*2; range = A018336.
LINKS
MATHEMATICA
f[n_] := If[Max[(p = FactorInteger[n][[;; , 1]])] <= 7, Times @@ p, 0]; Select[f /@ Range[300], # > 0 &] (* Amiram Eldar, Sep 06 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jul 15 2003
STATUS
approved