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A122256
Number of numbers <= n with 3-smooth Euler's totient (A000010).
1
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 20, 20, 21, 21, 22, 23, 24, 24, 25, 25, 26, 26, 27, 28, 29, 30, 31, 32, 33, 33, 34, 34, 34, 35, 35, 35, 36, 36, 36, 37, 38, 38, 39, 39, 40, 41, 41, 41, 42, 42, 42, 43, 44, 45, 45, 45, 46, 46, 47, 47, 48
OFFSET
1,2
COMMENTS
Partial sums of A122255.
MATHEMATICA
b[n_] := Boole[FactorInteger[EulerPhi[n]][[-1, 1]] <= 3];
Table[b[n], {n, 1, 100}] // Accumulate (* Jean-François Alcover, Oct 14 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Aug 29 2006
STATUS
approved