login
A317543
Positions of 1's in A317542, the formal inverse of the period-doubling sequence A096268.
2
1, 5, 7, 13, 17, 23, 29, 31, 37, 49, 55, 61, 65, 71, 77, 95, 101, 113, 119, 125, 127, 133, 145, 151, 157, 193, 199, 205, 223, 229, 241, 247, 253, 257, 263, 269, 287, 293, 305, 311, 317, 383, 389, 401, 407, 413, 449, 455, 461, 479, 485, 497, 503, 509, 511, 517, 529
OFFSET
0,2
LINKS
N. Rampersad and M. Stipulanti, The Formal Inverse of the Period-Doubling Sequence, arXiv preprint arXiv:1807.11899 [math.CO], 2018.
MATHEMATICA
a[0] = 1;
a[n_] :=
Module[{m, u, i},
u[0] = 0; u[1] = 1; u[2] = 0; u[3] = 0;
u[i_] := If[EvenQ[i], 0, If[IntegerQ[(i - 1)/4], u[2 ((i - 1)/4) - 1], u[(i - 3)/4]]];
m = a[n - 1] + 1;
While[u[m] == 0, m++];
m
]
CROSSREFS
KEYWORD
nonn
AUTHOR
Manon Stipulanti, Jul 30 2018
STATUS
approved