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A220846 a(n) = sum_(d|n) ((product_(d|n) d) / d). 1
1, 3, 4, 14, 6, 72, 8, 120, 39, 180, 12, 4032, 14, 336, 360, 1984, 18, 12636, 20, 16800, 672, 792, 24, 829440, 155, 1092, 1080, 43904, 30, 1944000, 32, 64512, 1584, 1836, 1680, 25474176, 38, 2280, 2184, 5760000, 42, 7112448, 44, 162624, 157950, 3312, 48 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Conjecture: sequence is injective (all terms of this sequence occur exactly once).

LINKS

Jaroslav Krizek, Table of n, a(n) for n = 1..100

FORMULA

a(n) = sum_(d|n) (A007955(n) / d).

a(p) = p + 1 for prime p.

EXAMPLE

The divisors of 6 are 1, 2, 3, 6. A007955(6) = product_(d|6) d = 1*2*3*6 = 36.

a(6) = 36/1 + 36/2 + 36/3 + 36/6 = 36 + 18 + 12 + 6 = 72.

CROSSREFS

Cf. A007955 (product of divisors of n.).

Sequence in context: A216868 A082732 A307893 * A009286 A076663 A277933

Adjacent sequences:  A220843 A220844 A220845 * A220847 A220848 A220849

KEYWORD

nonn

AUTHOR

Jaroslav Krizek, Dec 22 2012

STATUS

approved

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Last modified April 1 04:03 EDT 2020. Contains 333155 sequences. (Running on oeis4.)