A327634 - OEIS

A327634

Infinitary highly abundant numbers: numbers m such that isigma(m) > isigma(k) for all k < m, where isigma(k) is the sum of infinitary divisors of n (A049417).

1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 18, 21, 22, 24, 30, 40, 42, 54, 66, 72, 78, 88, 96, 102, 114, 120, 168, 210, 216, 264, 312, 330, 360, 378, 384, 408, 456, 480, 510, 546, 552, 600, 672, 690, 696, 744, 840, 1080, 1320, 1512, 1560, 1848, 1920, 2040, 2184, 2280, 2688

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

The infinitary version of A002093.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..930

EXAMPLE

The first 10 values of isigma(k) for k = 1 to 10 are: 1, 3, 4, 5, 6, 12, 8, 15, 10, 18. Record values are reached for all these values of k except for 7 and 9, therefore the sequence begins with 1, 2, 3, 4, 5, 6, 8, 10, ...

MATHEMATICA

f[p_, e_] := p^(2^(-1 + Position[Reverse @ IntegerDigits[e, 2], _?(# == 1 &)])); isigma[1] = 1; isigma[n_] := Times @@ (Flatten @ (f @@@ FactorInteger[n]) + 1); seq = {}; sm = 0; Do[s = isigma[n]; If[s > sm, sm = s; AppendTo[seq, n]], {n, 1, 10^4}]; seq

CROSSREFS

Cf. A002093, A037992, A049417, A285614, A292983.

Sequence in context: A029032 A218906 A059809 * A121492 A182418 A204580

Adjacent sequences: A327631 A327632 A327633 * A327635 A327636 A327637

KEYWORD

nonn,look

AUTHOR

Amiram Eldar, Sep 20 2019

STATUS

approved