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A146288 Number of divisors of the n-th prime signature number (A025487(n)). 4
1, 2, 3, 4, 4, 6, 5, 8, 8, 6, 9, 10, 12, 7, 12, 12, 16, 8, 15, 18, 14, 16, 16, 20, 9, 18, 24, 16, 24, 20, 24, 10, 21, 30, 18, 32, 24, 27, 28, 11, 32, 24, 36, 25, 36, 20, 40, 28, 36, 32, 12, 40, 27, 32, 48, 30, 42, 22, 48, 32, 45, 36, 13, 48, 30, 48, 60, 35, 48, 48, 24, 54, 50, 56 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A000005(A025487(n)).

If A025487(n)'s canonical factorization into prime powers is Product p^e(p), then a(n) = Product (e(p) + 1).

EXAMPLE

a(4)=4 because 4 positive integers divide evenly into A025487(4)=6: 1, 2, 3 and 6.

PROG

(Haskell)

a146288 = a000005 . a025487  -- Reinhard Zumkeller, Sep 17 2014

CROSSREFS

For the number of divisors of n, see A000005.

a(n) = sum of the n-th row of A146290, A146292.

A rearrangement of A080444.

Sequence in context: A117248 A343292 A079788 * A244361 A199424 A184160

Adjacent sequences:  A146285 A146286 A146287 * A146289 A146290 A146291

KEYWORD

nonn

AUTHOR

Matthew Vandermast, Nov 11 2008

STATUS

approved

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Last modified August 3 20:28 EDT 2021. Contains 346441 sequences. (Running on oeis4.)