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A344875 Multiplicative with a(2^e) = 2^(1+e) - 1, and a(p^e) = p^e - 1 for odd primes p. 19
1, 3, 2, 7, 4, 6, 6, 15, 8, 12, 10, 14, 12, 18, 8, 31, 16, 24, 18, 28, 12, 30, 22, 30, 24, 36, 26, 42, 28, 24, 30, 63, 20, 48, 24, 56, 36, 54, 24, 60, 40, 36, 42, 70, 32, 66, 46, 62, 48, 72, 32, 84, 52, 78, 40, 90, 36, 84, 58, 56, 60, 90, 48, 127, 48, 60, 66, 112, 44, 72, 70, 120, 72, 108, 48, 126, 60, 72, 78, 124, 80, 120 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A344878(n) * A344879(n).

Multiplicative with a(p^e) = A153151(p^e). - Antti Karttunen, Jul 01 2021

MATHEMATICA

f[2, e_] := 2^(e + 1) - 1; f[p_, e_] := p^e - 1; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Jun 03 2021 *)

PROG

(PARI) A344875(n) = { my(f=factor(n)~); prod(i=1, #f, (f[1, i]^(f[2, i]+(2==f[1, i]))-1)); };

CROSSREFS

Cf. A047994, A153151, A344876, A344877, A344878, A344879, A344969, A345947.

Sequence in context: A341911 A341916 A344878 * A178910 A182651 A175055

Adjacent sequences:  A344872 A344873 A344874 * A344876 A344877 A344878

KEYWORD

nonn,mult

AUTHOR

Antti Karttunen, Jun 03 2021

STATUS

approved

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Last modified December 6 01:25 EST 2021. Contains 349558 sequences. (Running on oeis4.)