A326414 Numbers which require exactly 288 'Reverse and Add' steps to reach a palindrome.

12000700000025339936491, 12000700001015339936491, 12000700002005339936491, 12000700010024339936491, 12000700011014339936491, 12000700012004339936491, 12000700020023339936491, 12000700021013339936491, 12000700022003339936491, 12000700030022339936491

Offset: 1

Author

Andrey S. Shchebetov and Sergei D. Shchebetov, Oct 18 2019

Keywords

• nonn
• base
• less

References

• Popular Computing (Calabasas, CA), The 196 Problem, Vol. 3 (No. 30, Sep 1975).

Links

• Sergei D. Shchebetov, Table of n, a(n) for n = 1..10000
• Jason Doucette, World Records
• Yutaka Nishiyama, Numerical Palindromes and the 196 Problem, International Journal of Pure and Applied Mathematics, Volume 80, No. 3, 2012, 375-384.
• Sergei D. Shchebetov, 19353600 terms (zipped file)
• R. Styer, The Palindromic Conjecture and the Fibonacci Sequence, Villanova University, 1986, 1-11.
• C. W. Trigg, Palindromes by Addition, Mathematics Magazine, 40 (1967), 26-28.
• C. W. Trigg, More on Palindromes by Reversal-Addition, Mathematics Magazine, 45 (1972), 184-186.
• Wikipedia, Lychrel Number
• 196 and Other Lychrel Numbers, 196 and Lychrel Number
• Index entries for sequences related to Reverse and Add!

Crossrefs

Cf. A023109, A033672, A065198, A065199, A065320, A065321, A065322, A065323, A065324, A065325, A065326, A065327, A070743, A072216, A072217, A072218, A281301, A281390, A281506, A281507.

Formula

Each term requires exactly 288 steps to turn into a 142-digit palindrome.

Extensions

Deleted an erroneous comment that said that the sequence was finite. - N. J. A. Sloane, Jun 23 2022