A003971 - OEIS

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A003971

Inverse Möbius transform of A003960.

1, 2, 3, 3, 4, 6, 5, 4, 7, 8, 7, 9, 8, 10, 12, 5, 10, 14, 11, 12, 15, 14, 13, 12, 13, 16, 15, 15, 16, 24, 17, 6, 21, 20, 20, 21, 20, 22, 24, 16, 22, 30, 23, 21, 28, 26, 25, 15, 21, 26, 30, 24, 28, 30, 28, 20, 33, 32, 31, 36, 32, 34, 35, 7, 32, 42, 35, 30, 39, 40, 37, 28, 38, 40

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

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

N. J. A. Sloane, Transforms.

FORMULA

Multiplicative with a(p^e) = e+1 if p = 2; (((p+1)/2)^(e+1) - 1)/((p-1)/2) if p > 2. - David W. Wilson, Sep 01 2001

MATHEMATICA

f[p_, e_] := (((p + 1)/2)^(e + 1) - 1)/((p - 1)/2); f[2, e_] := e + 1; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Dec 06 2022 *)

CROSSREFS

Cf. A003960.

Sequence in context: A347712 A159999 A003977 * A349371 A282442 A200668

Adjacent sequences: A003968 A003969 A003970 * A003972 A003973 A003974

KEYWORD

nonn,easy,mult

AUTHOR

Marc LeBrun

EXTENSIONS

More terms from Reiner Martin, Aug 15 2001

Formula corrected by Sean A. Irvine, Sep 26 2015

STATUS

approved