A354141 Indices of terms in A352808 that are powers of 2.

1, 2, 3, 5, 9, 22, 31, 61, 121, 247, 479, 951, 1862, 3802, 7431, 15180, 29723, 59766, 118893, 239999, 475573, 959341, 1902293, 3835229, 7609175, 15268473, 30436701, 61001391

Offset

1,2

Comments

Every power of 2 will eventually appear in A353730, so the sequence is infinite.

Links

Table of n, a(n) for n=1..28.

Rémy Sigrist, C++ program

Prog

(Python)
from itertools import count, islice
def ispow2(k): return bin(k).count("1") == 1
def agen(): # generator of terms
    A352808lst = [0, 1]; A352808set = {0, 1}
    k, mink, p = 1, 2, 2
    for n in count(2):
        if ispow2(k): yield n-1
        ahalf, k = A352808lst[n//2], mink
        while k in A352808set or k&ahalf: k += 1
        A352808lst.append(k); A352808set.add(k)
        while mink in A352808set: mink += 1
print(list(islice(agen(), 8))) # Michael S. Branicky, May 18 2022
(C++) See Links section.

Crossrefs

Cf. A352808, A353734.

Sequence in context: A365044 A349676 A287915 * A379694 A105180 A094206

Adjacent sequences: A354138 A354139 A354140 * A354142 A354143 A354144

Keyword

nonn,more

Author

N. J. A. Sloane, May 18 2022

Extensions

a(16)-a(22) from Michael S. Branicky, May 19 2022

a(23)-a(28) from Rémy Sigrist, May 21 2022

Status

approved