|
|
A001145
|
|
Describe the previous term! (method A - initial term is 7).
|
|
15
|
|
|
7, 17, 1117, 3117, 132117, 1113122117, 311311222117, 13211321322117, 1113122113121113222117, 31131122211311123113322117, 132113213221133112132123222117
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Method A = 'frequency' followed by 'digit'-indication.
a(n+1) - a(n) is divisible by 10^5 for n > 5. - Altug Alkan, Dec 04 2015
|
|
REFERENCES
|
S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 452-455.
I. Vardi, Computational Recreations in Mathematica. Addison-Wesley, Redwood City, CA, 1991, p. 4.
|
|
LINKS
|
|
|
EXAMPLE
|
E.g. the term after 3117 is obtained by saying "one 3, two 1's, one 7", which gives 132117.
|
|
MATHEMATICA
|
RunLengthEncode[x_List] := (Through[{First, Length}[ #1]] &) /@ Split[x]; LookAndSay[n_, d_: 1] := NestList[Flatten[Reverse /@ RunLengthEncode[ # ]] &, {d}, n - 1]; F[n_] := LookAndSay[n, 7][[n]]; Table[FromDigits[F[n]], {n, 1, 11}] (* Zerinvary Lajos, Jul 08 2009 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,base,easy,nice
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|