A369890 - OEIS

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A369890

The number of divisors of the largest divisor of n whose exponents in its prime factorization are all powers of 2.

1, 2, 2, 3, 2, 4, 2, 3, 3, 4, 2, 6, 2, 4, 4, 5, 2, 6, 2, 6, 4, 4, 2, 6, 3, 4, 3, 6, 2, 8, 2, 5, 4, 4, 4, 9, 2, 4, 4, 6, 2, 8, 2, 6, 6, 4, 2, 10, 3, 6, 4, 6, 2, 6, 4, 6, 4, 4, 2, 12, 2, 4, 6, 5, 4, 8, 2, 6, 4, 8, 2, 9, 2, 4, 6, 6, 4, 8, 2, 10, 5, 4, 2, 12, 4, 4

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OFFSET

1,2

COMMENTS

First differs from A369015 at n = 32.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A000005(A353897(n)).

Multiplicative with a(p^e) = A053644(e) + 1.

a(n) = 2 if and only if n is prime.

a(n) <= A000005(n), with equality if and only if n is in A138302.