A119398 -id:A119398 - cp's OEIS frontend

A119396 Numbers n such that A086793(n)=20.

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

Offset: 1

Zak Seidov, May 17 2006

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.

			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.

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

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

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

Edited by Robert Israel, Apr 03 2018

A119397 Numbers taking exactly 21 steps to reach 15 in A086793.

Original entry on oeis.org

71820, 103950, 127764, 135660, 141360, 161460, 173250, 183744, 193284, 203580, 206712, 209440, 214830, 217620, 221760, 223020, 223860, 234432, 243540, 244440, 246330, 247752, 256680, 263160, 264180, 265200, 280368, 281160, 286380, 287712

Offset: 1

Zak Seidov, May 18 2006

Some trajectories are: 71820,1104,168,102,36,46,18,30,27,22,9,13,5,6,12,19,11,3,4,7,8,15 103950,1134,168,... 127764,924,168,... 135660,1134,168,... 221760,1908,162,66,36,... 343728,1650,162,... 376992,2016,297,66,36,... All trajectories eventually join one of previous trajectories. In the first 136 terms <800000 there is only one odd number, 628425. Next odd terms are: 824175, 1340325, 1422135, 1495725 (see A119398).

Cf. A086793, A119396-A119415.

cp's OEIS Frontend

A119396 Numbers n such that A086793(n)=20.

Views

Author

Keywords

Comments

Examples

Links

Crossrefs

Programs

Maple