cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A306232 Numbers k such that the Reverse and Add! trajectory of k (presumably) does not reach a palindrome and does not join the trajectory or one of the reverse numbers of the trajectory of any term m < k.

Original entry on oeis.org

196, 879, 1997, 7059, 10553, 10563, 10577, 10583, 10585, 10638, 10663, 10668, 10697, 10715, 10728, 10735, 10746, 10748, 10783, 10785, 10787, 10788, 10877, 10883, 10963, 10965, 10977, 10983, 10985, 12797, 12898, 13097, 13197, 13694, 14096, 14698, 15297, 15597, 16999, 18598, 18798, 19098, 20459
Offset: 1

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Author

A.H.M. Smeets, Jan 30 2019

Keywords

Comments

The starting number k and its reverse are regarded as part of the trajectory, so palindromes are excluded from the sequence.
Sequence A063048 is similarly defined, except that we here include also the reverse numbers, which results in almost the same sequence as A063048.
The first difference is obtained for 10969 which is in A063048 but not in this sequence, due to the fact that the reversed number after the first iteration, 78701 is the reverse of 10787.
As a result, 16999 is included in this sequence while it is excluded in A063048, due to the fact that its number after the second iteration is 186571, which equals the number after the second iteration of 10969.

Crossrefs

Cf. A063048.

A344119 Numbers k whose trajectory under the Reverse and Add! operation carried out in base 16 does not reach a palindrome and (presumably) does not join the trajectory of any term m < k.

Original entry on oeis.org

413, 429, 443, 445, 3407, 3647, 3711, 3775, 3807, 3839, 4287, 7417, 12463, 12527, 16383, 24575, 28879, 45183, 45231, 49151, 57343, 61615, 61663, 61679, 66511, 66783, 67023, 67535, 67551, 67628, 67630, 67644, 67646, 67673, 67674, 67676, 67688, 67718, 67734
Offset: 1

Views

Author

A.H.M. Smeets, Aug 16 2021

Keywords

Comments

A number is considered here (presumably) a Lychrel number in base 16 if it does not reach a palindrome within 200 steps more than the actual record. Those record numbers of steps to become palindromic are known from data in other bases not to increase that much (see for instance A065198 and A065199 in case of base 10). Furthermore, a Lychrel number is considered not to reach the trajectory of any smaller Lychrel number if it does not reach a trajectory of a smaller Lychrel number within 100 steps more than the actual record. Again, those record numbers of steps to reach the trajectory of a smaller Lychrel number are known from data in other bases not to increase that much (see for instance A323975 and A323976 in case of base 10).

Crossrefs

In other bases: A075252 (2), A077405 (3), A075421 (4), A306596 (8), A063048 (10).
Cf. A065198, A065199, A323975, A323976.
Previous Showing 31-32 of 32 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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