A339134 Indices in A338884 where records occur.

1, 4, 12, 66, 346, 5876, 95078, 9411222, 1894078221

Offset: 1

Author

Ya-Ping Lu, Nov 24 2020

Keywords

• nonn
• base
• more

Comments

It seems that A338884(a(n)) = n and 3*sqrt(log(a(n)))/n ~ O(1).

Crossrefs

Cf. A000040, A070939, A208241, A338884.

Programs

Python

from sympy import isprime
def search(n):
    k = 1
    while 1:
        i = k*n + 1
        while i < k*n + k:
            if isprime(i) == 1: return i
            i += 2
        k = 2*k
a_rec = 0
n = 1
while 1:
    m = search(n)
    a = m.bit_length() - n.bit_length()
    if a > a_rec:
        print(n)
        a_rec = a
    n += 1