|
|
A341257
|
|
Positions of palindromes in the ordering of all 01-words defined at A341256.
|
|
1
|
|
|
1, 2, 3, 6, 7, 9, 12, 14, 15, 21, 24, 30, 31, 35, 41, 45, 48, 52, 58, 62, 63, 75, 81, 93, 96, 108, 114, 126, 127, 135, 147, 155, 161, 169, 181, 189, 192, 200, 212, 220, 226, 234, 246, 254, 255, 279, 291, 315, 321, 345, 357, 381, 384, 408, 420, 444, 450, 474
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
|
|
LINKS
|
|
|
EXAMPLE
|
Among the first 20 words (0, 1, 00, 10, 01, 11, 000, 100, 010, 110, 001, 101, 011, 111, 0000, 1000, 0100, 1100, 0010, 1010), there are 9 palindromes: 0, 1, 00, 11, 000, 010, 101, 111, 0000, beginning in positions 1, 2, 3, 6, 7, 9, 12, 14, 15, respectively.
|
|
MATHEMATICA
|
z = 800; s = Table[2 n - 1, {n, 1, z}];
t = Complement[Range[Max[s]], s];
s1[n_] := Length[Intersection[Range[n - 1], s]];
t1[n_] := n - 1 - s1[n];
w[1] = {0}; w[t[[1]]] = {1};
w[n_] := If[MemberQ[s, n], Join[{0}, w[s1[n]]], Join[{1}, w[t1[n]]]]
tt = Table[w[n], {n, 1, z}]; Select[tt, # == Reverse[#] &]
p = Select[Range[Length[tt]], tt[[#]] == Reverse[tt[[#]]] &]
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|