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A151946
a(1) = 8127; thereafter a(n) = (a(n-1) with digits sorted into descending order) - (a(n-1) with digits sorted into ascending order) (see the Kaprekar map,
A151949
).
2
8127, 7443, 3996, 6264, 4176, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174, 6174
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OFFSET
1,1
COMMENTS
Similar in spirit to the RATS (Reverse, Add Then Sort) sequences.
Converges to the fixed point 6174. For the list of fixed points see
A099009
.
The initial value 1001 is the smallest number that converges to 6174 - see
A151967
.
LINKS
Table of n, a(n) for n=1..39.
John Tierney,
"TierneyLab" column, New York Times, Section C, Aug 18 2009
Index entries for the Kaprekar map
Index entries for RATS sequences
Index entries for linear recurrences with constant coefficients
, signature (1).
MATHEMATICA
NestList[FromDigits[ReverseSort[#]] - FromDigits[Sort[#]] & [IntegerDigits[#]] &, 8127, 49] (* or *)
PadRight[{8127, 7443, 3996, 6264, 4176}, 50, 6174] (*
Paolo Xausa
, Jan 24 2026 *)
CROSSREFS
Cf.
A099009
,
A151947
,
A151949
,
A151951
,
A151955
,
A151956
,
A151967
.
A151968
.
Sequence in context:
A209845
A025288
A025306
*
A229381
A147633
A237145
Adjacent sequences:
A151943
A151944
A151945
*
A151947
A151948
A151949
KEYWORD
nonn
,
base
AUTHOR
N. J. A. Sloane
, Aug 18 2009
STATUS
approved