A355670 Numbers k such that A246600(k) < A000005(k).

2, 4, 6, 8, 9, 10, 12, 14, 16, 18, 20, 21, 22, 24, 25, 26, 28, 30, 32, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 46, 48, 49, 50, 52, 54, 55, 56, 57, 58, 60, 62, 64, 65, 66, 68, 69, 70, 72, 74, 75, 76, 77, 78, 80, 81, 82, 84, 86, 87, 88, 90, 91, 92, 93, 94, 96

Offset: 1

Author

Chai Wah Wu, Dec 19 2022

Keywords

• nonn
• base

Comments

Numbers k such that bitwise OR(k, d_1, d_2, ... d_m) > k where d_1, ..., d_m are the divisors of k.

Complement of A359080.

First 21 terms coincide with A336376.

A102554 is a subsequence; this sequence contains 1, 135, 175, 243, 343, 351, 363, ... which are not in A102554.

Crossrefs

Cf. A000005, A102553, A102554, A246600, A336375, A359080.

Programs

Python

from itertools import count, islice
from operator import ior
from functools import reduce
from sympy import divisors
def A355670_gen(startvalue=1): # generator of terms >= startvalue
    return filter(lambda n:n|reduce(ior,divisors(n,generator=True))>n,count(max(startvalue,1)))
A355670_list = list(islice(A355670_gen(), 20))