A092210 Positive integers n such that the trajectory of n under the Reverse and Add! operation carried out in base 2 (presumably) does not join the trajectory of any m < n.

1, 16, 64, 74, 98, 107, 259, 266, 271, 275, 298, 398, 442, 454, 522, 794, 911, 1027, 1046, 1057, 1066, 1070, 1073, 1076, 1081, 1082, 1085, 1115, 1274, 1422, 1562, 1570, 1967, 2070, 2329, 3106, 3355, 3871, 4099, 4114, 4120, 4126, 4136, 4152, 4182, 4189

Offset

1,2

Comments

The conjecture that the base 2 trajectories of the terms do not join is based on the observation that if the trajectories of two integers < 12000 join, this happens after at most 93 steps, while for any two terms listed above the trajectories do not join within 1000 steps. For pairs from 1, 16, 64, 74, 98, 107 this has even been checked for 5000 steps.

Base-2 analog of A070788 (base 10) and A091675 (base 4).

Links

Table of n, a(n) for n=1..46.

Index entries for sequences related to Reverse and Add!

Example

The trajectory of 2 is part of the trajectory of 1 (cf. A035522); the trajectory of 16 does not join the trajectory of 1 within 10000 steps; the trajectory of 64 does not join the trajectory of 1 or of 16 within 10000 steps.

Mathematica

limit = 10^3; (* Assumes that there is no palindrome if none is found before "limit" iterations *)
utraj = NestList[# + IntegerReverse[#, 2] &, 1, limit];
Flatten@{1, Select[Range[2, 4189],   (l = Length@NestWhileList[# + IntegerReverse[#, 2] &, #, ! MemberQ[utraj, #] &, 1, limit];
  utraj = Union[utraj, NestList[# + IntegerReverse[#, 2] &, #, limit]];
  l == limit + 1) &]} (* Robert Price, Nov 03 2019 *)

Crossrefs

Cf. A035522, A075252, A070788, A091675.

Sequence in context: A255660 A303797 A118902 * A320892 A365263 A062320

Adjacent sequences: A092207 A092208 A092209 * A092211 A092212 A092213

Keyword

nonn,base

Author

Klaus Brockhaus, Feb 25 2004

Status

approved