A241174 Smallest number requiring n steps to reach a palindrome under the "add a digit" process described in A241173.

0, 10, 13, 12, 17, 89, 1072, 1066, 1058, 1049, 1045, 1039, 1036, 1028, 1019, 1017, 1009, 1007, 998, 994, 988, 100953, 100944, 100935, 100926, 100917, 100908, 100899, 100890, 100882, 100874, 100866, 100858, 100849, 100841, 100833, 100825, 100817, 100809, 100801, 100792, 100784, 100777

Offset

0,2

Comments

Beginning with a(6), the palindromic sinks appear to be, for positive n, (10^n+1)*(10^(n+1)+1):

n=1 a(6)-a(20) 1072 to 988

n=2 a(21)-a(157) 100953 to 99980

n=3 a(158)-a(1461) 10^7+9827 to 10^7-20

n=4 a(1462)-a(14078) 10^9+98720 to 10^9-20

n=5 a(14079)-a(137233) 10^11+988091 to 10^11-20

n=6 a(137234)-a(1346435) 10^13+9885167 to 10^13-20

n=7 a(1346436)-a(13265907) 10^15+98879696 to 10^15-20

etc. - Hans Havermann, Apr 23 2014

References

Eric Angelini, Posting to Sequence Fans Mailing List, Apr 20 2014

Links

Hans Havermann, Table of n, a(n) for n = 0..1500

Mathematica

A241173[n_] := Module[{c, nx},
   If[n == IntegerReverse[n], Return[0]];
   c = 1; nx = n;
   While[ ! AnyTrue[nx = Union[Flatten[nx + IntegerDigits[nx]]], # == IntegerReverse[#] &], c++];
   Return[c]];
A241174[n_] := Module[{i = 0},
   While[A241173[i] != n, i++];
   Return[i]];
Table[A241174[i], {i, 0, 5}] (* Robert Price, Mar 17 2019 *)

Crossrefs

Cf. A241173, A002113.

Related sequences: A241173, A241174, A241175, A241176, A241177, A241178, A241179, A241180, A241181, A241182, A241183.

Sequence in context: A248336 A332478 A144814 * A092887 A131365 A241144

Adjacent sequences: A241171 A241172 A241173 * A241175 A241176 A241177

Keyword

nonn,base

Author

N. J. A. Sloane, Apr 23 2014

Extensions

More terms from Hans Havermann, Apr 23 2014

Status

approved