A347306 When k appears in A347113, or -1 if k never appears.

1, 8, 11, 2, 7, 9, 20, 12, 15, 3, 28, 13, 19, 10, 16, 21, 37, 17, 51, 23, 27, 4, 53, 24, 33, 14, 29, 34, 47, 25, 101, 30, 38, 22, 43, 31, 116, 18, 44, 39, 58, 45, 63, 48, 52, 5, 99, 49, 59, 54, 68, 60, 81, 55, 64, 50, 73, 35, 136, 56, 146, 26, 65, 69, 72, 66, 159, 74, 77, 70, 153

Offset

1,2

Comments

It is conjectured that every positive number appears in A347113. - N. J. A. Sloane, Nov 08 2021

Links

Michael De Vlieger, Table of n, a(n) for n = 1..10000 (first 3330 terms from N. J. A. Sloane)

Hugo Pfoertner, Table of n, a(n) for n = 1..132708

Hugo Pfoertner, Illustration of terms corresponding to first 400000 terms of A347113, use zoom to see details.

Mathematica

With[{s = Import["https://oeis.org/A347113/b347113.txt", "Data"][[All, -1]]}, Array[FirstPosition[s, #][[1]] &, 71]] (* Michael De Vlieger, Sep 01 2021 *)

Prog

(Python)
from math import gcd
def A347306(n):
    if n == 1:
        return 1
    i, j, nset, m = 1, 2, {1}, 2
    while True:
        k = m
        i += 1
        while k == j or gcd(k, j) == 1 or k in nset:
            k += 1
        if k == n:
            return i
        j = k+1
        nset.add(k)
        while m in nset:
            m += 1 # Chai Wah Wu, Sep 02 2021

Crossrefs

Cf. A347113.

Sequence in context: A222299 A070478 A306527 * A109596 A164801 A156925

Adjacent sequences: A347303 A347304 A347305 * A347307 A347308 A347309

Keyword

nonn

Author

N. J. A. Sloane, Sep 01 2021

Status

approved