OFFSET
1,1
COMMENTS
Conjecture: every prime appears in A347113 (every number, in fact).
The graph shows three three strong lines (and many other points). Can the primes on the three lines be described in a simple way?
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..10000
PROG
(Python)
from math import gcd
from sympy import prime
def A347313(n):
p = prime(n)
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 == p:
return i
j = k+1
nset.add(k)
while m in nset:
m += 1 # Chai Wah Wu, Sep 06 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Sep 06 2021
STATUS
approved