A322027 - OEIS

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A322027

Maximum order of primeness among the prime factors of n; a(1) = 0.

0, 1, 2, 1, 3, 2, 1, 1, 2, 3, 4, 2, 1, 1, 3, 1, 2, 2, 1, 3, 2, 4, 1, 2, 3, 1, 2, 1, 1, 3, 5, 1, 4, 2, 3, 2, 1, 1, 2, 3, 2, 2, 1, 4, 3, 1, 1, 2, 1, 3, 2, 1, 1, 2, 4, 1, 2, 1, 3, 3, 1, 5, 2, 1, 3, 4, 2, 2, 2, 3, 1, 2, 1, 1, 3, 1, 4, 2, 1, 3, 2, 2, 2, 2, 3, 1, 2

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OFFSET

1,3

COMMENTS

The order of primeness (A078442) of a prime number p is the number of times one must apply A000720 to obtain a nonprime number.

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..65536

N. Fernandez, An order of primeness, F(p)

N. Fernandez, An order of primeness [cached copy, included at A006450 with permission of the author]

EXAMPLE

a(105) = 3 because the prime factor of 105 = 3*5*7 with maximum order of primeness is 5, with order 3.

MAPLE