A285385 Positions of 1 in A285384; complement of A072939.

1, 2, 4, 5, 6, 8, 10, 12, 13, 14, 16, 17, 18, 20, 21, 22, 24, 26, 28, 29, 30, 32, 34, 36, 37, 38, 40, 42, 44, 45, 46, 48, 49, 50, 52, 53, 54, 56, 58, 60, 61, 62, 64, 65, 66, 68, 69, 70, 72, 74, 76, 77, 78, 80, 81, 82, 84, 85, 86, 88, 90, 92, 93, 94, 96, 98

Offset

1,2

Links

Clark Kimberling, Table of n, a(n) for n = 1..10000

Formula

a(n) = A171946(n) for n>=2.

a(n + 1) = a(n) + A096268(a(n) - 1) + 1 for all n > 0. (conjecture) - Velin Yanev, Mar 23 2019

Example

As a word, A285384 = 11011101..., in which the positions of 1 are 1,2,4,5,6,8,...

Mathematica

s = Nest[Flatten[# /. {0 -> {1, 1}, 1 -> {0, 1}}] &, {0}, 16] (* A285384 *)
Flatten[Position[s, 0]]  (* A072939 *)
Flatten[Position[s, 1]]  (* A285385 *)

Prog

(Python)
def A285385(n):
    def f(x):
        c, s = n, bin(x-1)[2:]
        l = len(s)
        for i in range(l&1, l, 2):
            c += int(s[i])+int('0'+s[:i], 2)
        return c
    m, k = n, f(n)
    while m != k: m, k = k, f(k)
    return m # Chai Wah Wu, Jan 29 2025

Crossrefs

Cf. A072939, A171946, A285384.

Sequence in context: A192584 A337140 A171946 * A026435 A026437 A026441

Adjacent sequences: A285382 A285383 A285384 * A285386 A285387 A285388

Keyword

nonn,easy

Author

Clark Kimberling, Apr 26 2017

Status

approved