A151967 Iterate the Kaprekar map of A151949 starting at the n-digit number 100...01; sequence gives the lowest number in the resulting cycle.

0, 0, 6174, 62964, 420876, 7509843, 64308654, 864197532, 6431088654, 86420987532, 643310886654, 8643209876532, 43333208766666, 885432098765412, 6543331088666544, 88754320987654212, 643111110888888654

Offset

2,3

Links

Joseph Myers, Table of n, a(n) for n=2..1000 [From Joseph Myers, Aug 21 2009]

Index entries for the Kaprekar map

Example

a(6) = 420876: 100001 -> 109989 -> 980811 -> 976221 -> 853542 -> 620874 -> 851742 -> 750843 -> 840852 -> 860832 -> 862632 -> 642654 -> 420876 -> 851742 -> ..., a cycle of length 7 with smallest member 420876.

Mathematica

(Mma program from Harvey P. Dale) To find the first 20 terms of the trajectory of 10001, for instance:
f[n_]:=Module[{idn=IntegerDigits[n], idns}, idns=Sort[idn]; Abs[FromDigits[ idns]-FromDigits[Reverse[idns]]]]
NestList[f, 10001, 20]

Crossrefs

See A151968 for the length of the cycles. Cf. A151957, A151958.

Different from A151957.

Sequence in context: A033288 A266586 A057880 * A214556 A114930 A068757

Adjacent sequences: A151964 A151965 A151966 * A151968 A151969 A151970

Keyword

nonn,base

Author

N. J. A. Sloane, Aug 20 2009

Extensions

Extended by Joseph Myers, Aug 21 2009

Status

approved