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A119396 Numbers n such that A086793(n)=20. 3
924, 1104, 1134, 1540, 1650, 1760, 1820, 1908, 1992, 2016, 2288, 2556, 2632, 2744, 2860, 2940, 2970, 3000, 3192, 3204, 3220, 3248, 3400, 3630, 3738, 3784, 3840, 3852, 3880, 3968, 3990, 4134, 4260, 4410, 4464, 4674, 4736, 4860, 4875, 4930, 4992, 5016 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Some trajectories are: 924,168,102,36,46,18,30,27,22,9,13,5,6,12,19,11,3,4,7,8,15 1104,168,102,... 1540,162,66,36,... 1650,162,66,36,... 2016,297,66,36,... 2940,297,66,36,... 3192,312,102,36,... All trajectories eventually join one of previous trajectories.

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

EXAMPLE

924 is a term because it reaches 15 in 20 steps with this trajectory 924,168,102,36,46,18,30,27,22,9,13,5,6,12,19,11,3,4,7,8,15.

MAPLE

f:= proc(n) option remember; local t;

  if kernelopts(level) > 460 then return FAIL fi;

  t:= add(convert(convert(d, base, 10), `+`), d=numtheory:-divisors(n));

  1+procname(t)

end proc:

f(15):= 0:

f(1):= FAIL:

Res:= NULL: count:= 0:

for n from 1 while count < 100 do

  if f(n) = 20 then

    count:= count+1;

    Res:= Res, n;

   fi

od:

Res; # Robert Israel, Apr 03 2018

CROSSREFS

Cf. A034690, A086793, A094501, A095347, A114527, A118358, A119397, A119398, A260059.

Sequence in context: A228673 A268849 A177810 * A121943 A024750 A024758

Adjacent sequences:  A119393 A119394 A119395 * A119397 A119398 A119399

KEYWORD

base,nonn

AUTHOR

Zak Seidov, May 17 2006

EXTENSIONS

Edited by Robert Israel, Apr 03 2018

STATUS

approved

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Last modified September 23 20:42 EDT 2021. Contains 347617 sequences. (Running on oeis4.)