A355670 - OEIS

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

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OFFSET

1,1

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.

LINKS

Table of n, a(n) for n=1..66.

PROG

(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))

CROSSREFS

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

Sequence in context: A047412 A282760 A355529 * A336375 A353683 A296214

Adjacent sequences: A355667 A355668 A355669 * A355671 A355672 A355673

KEYWORD

nonn,base

AUTHOR

Chai Wah Wu, Dec 19 2022

STATUS

approved