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A335055 Odd infinitary abundant numbers whose infinitary abundancy is closer to 2 than that of any smaller odd infinitary abundant number. 3
945, 29835, 33345, 43065, 46035, 49875, 83265, 354585, 359205, 361515, 366135, 382305, 389235, 400785, 403095, 407715, 414645, 416955, 423885, 430815, 437745, 442365, 77967015, 132335385, 210124665, 719709375, 724239285, 1756753845, 9665740455, 10394173335 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The infinitary abundancy of a number k is isigma(k)/k, where isigma(k) is the sum of infinitary divisors of k (A049417).

LINKS

Table of n, a(n) for n=1..30.

EXAMPLE

The infinitary abundancies of the first terms are 2.031..., 2.027..., 2.015..., 2.006..., 2.001..., ...

MATHEMATICA

fun[p_, e_] := Module[{b = IntegerDigits[e, 2]}, m = Length[b]; Product[If[b[[j]] > 0, 1 + p^(2^(m - j)), 1], {j, 1, m}]]; isigma[1] = 1; isigma[n_] := Times @@ fun @@@ FactorInteger[n]; seq = {}; r = 3; Do[s = isigma[n]/n; If[s > 2 && s < r, AppendTo[seq, n]; r = s], {n, 1, 10^5, 2}]; seq

CROSSREFS

Cf. A049417, A127666, A188263, A335052, A335053, A335054.

Sequence in context: A274756 A335053 A290034 * A133818 A334973 A334975

Adjacent sequences:  A335052 A335053 A335054 * A335056 A335057 A335058

KEYWORD

nonn

AUTHOR

Amiram Eldar, May 21 2020

STATUS

approved

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Last modified November 27 03:49 EST 2021. Contains 349345 sequences. (Running on oeis4.)