A134672 - OEIS

A134672

Inverse Mobius transform of the superabundant numbers, A051731 * A004394.

1, 3, 5, 9, 13, 31, 37, 57, 65, 135, 181, 277, 361, 759, 857, 1317, 1681, 2611, 5041, 10221, 15161, 25383, 27721, 55765, 110893, 166683, 277265, 333405, 554401, 666283, 720721, 1442757, 2162345, 3605283, 4324369, 7210057, 8648641, 10815843, 21621965, 36766989

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OFFSET

1,2

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..1000

FORMULA

Inverse Mobius transform of A004394

EXAMPLE

a(4) = 9 = (1, 1, 0, 1) dot (1, 2, 4, 6) = (1 + 2 + 0 + 6), where (1, 1, 0, 1) = row four of A051731.

MATHEMATICA

sa={}; rm=0; Do[r=DivisorSigma[1, n]/n; If[r>rm, rm=r; AppendTo[sa, n]], {n, 1, 120000}]; s={}; Do[AppendTo[s, DivisorSum[j, sa[[#]]&]], {j, 1, Length[sa]}]; s (* Amiram Eldar, Jun 28 2019 *)

CROSSREFS

Cf. A004394, A051731.

Sequence in context: A145365 A306833 A146433 * A321024 A211389 A335193

Adjacent sequences: A134669 A134670 A134671 * A134673 A134674 A134675

KEYWORD

nonn

AUTHOR

Gary W. Adamson, Nov 05 2007

EXTENSIONS

More terms from Amiram Eldar, Jun 28 2019

STATUS

approved