A341257 Positions of palindromes in the ordering of all 01-words defined at A341256.

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

Offset: 1

Author

Clark Kimberling, Mar 16 2021

Keywords

• nonn

Comments

Also, the positions in A076478 of palindromes. - Clark Kimberling, Aug 16 2021

Examples

			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.
		

Crossrefs

Cf. A341256.

Appears to equal A044051 - 2. - Hugo Pfoertner, Mar 16 2021

Programs

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[[#]]] &]