|
|
A214215
|
|
List of subwords (or factors) of the Thue-Morse "1,2"-word A001285.
|
|
1
|
|
|
1, 2, 11, 12, 21, 22, 112, 121, 122, 211, 212, 221, 1121, 1122, 1211, 1212, 1221, 2112, 2121, 2122, 2211, 2212, 11212, 11221, 12112, 12122, 12211, 12212, 21121, 21122, 21211, 21221, 22112, 22121, 112122, 112211, 112212, 121121, 121122, 121221, 122112, 122121
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
The number of factors of length m is given by A005942(m).
|
|
LINKS
|
|
|
MAPLE
|
b:= proc(n) option remember; local r;
`if`(n=0, 1, `if`(n<4, 2*n, `if`(irem(n, 2, 'r')=0,
b(r)+b(r+1), 2*b(r+1))))
end:
m:= proc(n) option remember; local r;
`if`(n=0, 1, `if`(irem(n, 2, 'r')=0, m(r), 3-m(r)))
end:
T:= proc(n) local k, s; s:={};
for k while nops(s)<b(n) do
s:= s union {parse(cat(seq(m(i), i=k..k+n-1)))}
od; sort([s[]])[]
end:
|
|
MATHEMATICA
|
b[n_] := b[n] = Module[{r}, If[n == 0, 1, If[n < 4, 2n, r = Quotient[n, 2]; If[Mod[n, 2] == 0, b[r] + b[r + 1], 2b[r + 1]]]]];
m[n_] := m[n] = Module[{r}, If[n == 0, 1, r = Quotient[n, 2]; If[Mod[n, 2] == 0, m[r], 3 - m[r]]]];
T[n_] := Module[{k, s = {}}, For[k = 1, Length[s] < b[n], k++, s = s ~Union~ {FromDigits[#]}& @ Table[m[i], {i, k, k + n - 1}]]; Sort[s]];
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|