This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A151946 #5 Mar 30 2012 16:51:07 %S A151946 8127,7443,3996,6264,4176,6174,6174,6174,6174,6174,6174,6174,6174, %T A151946 6174,6174,6174,6174,6174,6174,6174,6174,6174,6174,6174,6174,6174, %U A151946 6174,6174,6174,6174,6174,6174,6174,6174,6174,6174,6174,6174,6174 %N 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). %C A151946 Similar in spirit to the RATS (Reverse, Add Then Sort) sequences. %C A151946 Converges to the fixed point 6174. For the list of fixed points see A099009. %C A151946 The initial value 1001 is the smallest number that converges to 6174 - see A151967. %H A151946 John Tierney, <a href="http://nytimes.com/tierneylab">"TierneyLab" column, New York Times, Section C, Aug 18 2009</a> %H A151946 <a href="/index/K#Kaprekar_map">Index entries for the Kaprekar map</a> %H A151946 <a href="/index/Ra#RATS">Index entries for RATS sequences</a> %Y A151946 Cf. A099009, A151947, A151949, A151951, A151955, A151956, A151967. A151968. %K A151946 nonn,base %O A151946 1,1 %A A151946 _N. J. A. Sloane_, Aug 18 2009