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A334455 a(n) is unique integer k such that sigma(A051281(n)) = tau(A051281(n))^k (where sigma is the sum of divisors (A000203) and tau the number of divisors (A000005)), with a(1) = 1. 1
1, 2, 3, 5, 7, 4, 5, 4, 6, 13, 5, 8, 17, 6, 9, 19, 10, 10, 7, 11, 11, 8, 8, 12, 12, 13, 9, 9, 7, 6, 15, 31, 8, 16, 11, 17, 12, 18, 18, 19, 13, 13, 13, 8, 10, 10, 11, 11, 22, 9, 12, 24, 10, 25, 17, 17, 13, 13, 14, 14, 14, 19, 12, 12, 15, 15, 61, 21, 16, 32, 13 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..12885

Rémy Sigrist, Colored scatterplot of the first 12885 terms (where the color is function of tau(A051281(n)))

Rémy Sigrist, PARI program for A334455

FORMULA

a(n) = log(A000203(A051281(n))) / log(A000005(A051281(n))) for n > 1.

EXAMPLE

For n = 7:

- A051281(7) = 889,

- sigma(889) = 1024,

- tau(889) = 4,

- 1024 = 4^5,

- so a(7) = 5.

PROG

(PARI) See Links section.

CROSSREFS

Cf. A000005, A000203, A051281, A225369.

Sequence in context: A126607 A124322 A209037 * A075241 A239694 A097883

Adjacent sequences:  A334452 A334453 A334454 * A334456 A334457 A334458

KEYWORD

nonn

AUTHOR

Rémy Sigrist, Nov 10 2020

STATUS

approved

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Last modified September 20 04:16 EDT 2021. Contains 347577 sequences. (Running on oeis4.)