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A069915 Sum of (1+phi)-divisors of n (cf. A061389). 3
1, 3, 4, 3, 6, 12, 8, 7, 4, 18, 12, 12, 14, 24, 24, 11, 18, 12, 20, 18, 32, 36, 24, 28, 6, 42, 13, 24, 30, 72, 32, 31, 48, 54, 48, 12, 38, 60, 56, 42, 42, 96, 44, 36, 24, 72, 48, 44, 8, 18, 72, 42, 54, 39, 72, 56, 80, 90, 60, 72, 62, 96, 32, 35, 84, 144, 68, 54, 96, 144, 72 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

FORMULA

Multiplicative with a(p^e) = 1+Sum_{k=1..e, gcd(k, e)=1} p^k.

MATHEMATICA

a[1] = 1; a[p_?PrimeQ] = p + 1; a[n_] := Times @@ (1 + Sum[If[GCD[k, Last[#]] == 1, First[#]^k, 0], {k, 1, Last[#]}] & ) /@ FactorInteger[n]; Table[a[n], {n, 1, 71}] (* Jean-Fran├žois Alcover, May 04 2012 *)

PROG

(Haskell)

a069915 n = product $ zipWith sum_1phi (a027748_row n) (a124010_row n)

   where sum_1phi p e = 1 + sum [p ^ k | k <- a038566_row e]

-- Reinhard Zumkeller, Mar 13 2012

CROSSREFS

Cf. A061389.

Cf. A027748, A124010, A038566, A051378.

Sequence in context: A046897 A109506 A000113 * A033634 A111970 A291317

Adjacent sequences:  A069912 A069913 A069914 * A069916 A069917 A069918

KEYWORD

mult,nonn

AUTHOR

Vladeta Jovovic, Apr 23 2002

STATUS

approved

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Last modified June 17 06:06 EDT 2019. Contains 324183 sequences. (Running on oeis4.)