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A348414
Numbers with record values of the denominator of the harmonic mean of their divisors.
3
1, 2, 4, 8, 16, 36, 64, 100, 128, 144, 256, 324, 400, 512, 576, 900, 1296, 1600, 1936, 2304, 3600, 5184, 6400, 8100, 9216, 10404, 11664, 14400, 17424, 20736, 22500, 30276, 32400, 41616, 46656, 57600, 76176, 90000, 108900, 129600, 166464, 202500, 230400, 260100
OFFSET
1,2
COMMENTS
The corresponding record values are 1, 3, 7, 15, 31, 91, 127, 217, 255, 403, ... (see the link for more values).
EXAMPLE
The first 4 terms of A099378 are 1, 3, 2 and 7. The record values, 1, 3 and 7, occur at 1, 2 and 4, the first 3 terms of this sequence.
MATHEMATICA
d[n_] := Denominator[DivisorSigma[0, n]/DivisorSigma[-1, n]]; dm = 0; s = {}; Do[dn = d[n]; If[dn > dm, dm = dn; AppendTo[s, n]], {n, 1, 10^6}]; s
CROSSREFS
Sequence in context: A085294 A195327 A266544 * A333051 A034340 A034341
KEYWORD
nonn
AUTHOR
Amiram Eldar, Oct 17 2021
STATUS
approved