A240510 Numbers whose "reverse and add" process becomes palindromic at 8813200023188.

89, 98, 187, 286, 385, 583, 682, 781, 869, 880, 968, 1297, 1387, 1477, 1567, 1657, 1747, 1837, 1927, 2296, 2386, 2476, 2566, 2656, 2746, 2836, 2926, 3295, 3385, 3475, 3565, 3655, 3745, 3835, 3925, 4294, 4384, 4474, 4564, 4654, 4744, 4834, 4924, 5293, 5383

Offset: 1

Author

J. Lowell, Apr 06 2014

Keywords

• base
• nonn
• fini

Comments

The "reverse and add" sequence for 178 includes 8813200023188, but it becomes palindromic at 15851, so 178 is not in this sequence.

See interesting patterns of the first differences in A328492. - Robert Price, Oct 16 2019

References

• David Wells, The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books, NY, 1986, Revised edition 1987. See p. 143.

Links

• Daniel Starodubtsev, Table of n, a(n) for n = 1..100000 (terms 1..177 from Robert Price)
• Felix Fröhlich, C++ program for this sequence.

Crossrefs

Cf. A033670, A328492.

Programs

Mathematica

limit = 10^3; (* Assumes that there is no palindrome if none is found before "limit" iterations *)
Select[Range[0, 50000], (np = #; i = 0;
   While[ ! PalindromeQ[np] && i < limit,
    np = np + IntegerReverse[np]; i++];
np == 8813200023188) &] (* Robert Price, Oct 16 2019 *)

PARI

is(n)=my(k=8813200023188); while(n<=k && (d=digits(n))!=(r=Vecrev(d)), n+=fromdigits(r)); n==k; \\ Charles R Greathouse IV, Apr 09 2020

Extensions

More terms from Jon E. Schoenfield, Apr 12 2014