A370607 2-valuations of terms of A370606.

0, 1, 2, 4, 5, 6, 8, 9, 12, 13, 16, 18, 19, 20, 21, 22, 25, 26, 27, 30, 31, 33, 36, 37, 39, 41, 42, 43, 44, 45, 46, 47, 48, 50, 52, 55, 56, 57, 59, 60, 63, 66, 67, 68, 69, 70, 71, 75, 77, 78, 81, 82, 85, 86, 87, 88, 89, 92, 93, 94, 95, 96, 98, 99, 100, 103, 104

Offset: 1

Author

Joerg Arndt, Feb 23 2024

Keywords

• nonn

Links

• Chai Wah Wu, Table of n, a(n) for n = 1..2000

Programs

PARI

r=-1;forprime(p=2,10^12,v=valuation(p-1,2);if(v>r,print1(v,", ");r=v));

Python

from itertools import count, islice
from sympy import isprime
def A370607_gen(): # generator of terms
    a = 1
    while True:
        for q in count(a,a):
            if isprime(q+1):
                yield (b:=q&-q).bit_length()-1
                a = b<<1
                break
A370607_list = list(islice(A370607_gen(),30)) # Chai Wah Wu, Feb 23 2024

Extensions

a(21)-a(67) from Chai Wah Wu, Feb 23 2024