A353185 Numbers which require exactly 289 'Reverse and Add' steps to reach a palindrome.

10037000230509917799950, 10037000240508917799950, 10037000250507917799950, 10037000260506917799950, 10037000270505917799950, 10037000280504917799950, 10037000290503917799950, 10037000330509817799950, 10037000340508817799950

Offset

1,1

Comments

The sequence starts with 10037000230509917799950, ends with 15999771990503200073000 and contains 9031680 terms known at present, including 13968441660506503386020 and 13568441660506503386420 discovered by Anton Stefanov on January 5, 2021.

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, 9031680 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!

Formula

Each term requires exactly 289 steps to turn into a 142-digit palindrome.

Crossrefs

A023109, A033672, A065198, A065199, A065320, A065321, A065322, A065323, A065324, A065325, A065326, A065327, A070743, A072216, A072217, A072218, A281301, A281390, A281506, A281507, A326414.

Sequence in context: A343266 A330009 A171265 * A180247 A095440 A326414

Adjacent sequences: A353182 A353183 A353184 * A353186 A353187 A353188

Keyword

nonn,base

Author

Andrey S. Shchebetov and Sergei D. Shchebetov, Apr 29 2022

Status

approved