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A365408
Numbers j whose largest divisor <= sqrt(j) is not a power of 2.
2
9, 12, 15, 18, 21, 25, 27, 30, 33, 35, 36, 39, 40, 42, 45, 48, 49, 50, 51, 54, 55, 56, 57, 60, 63, 65, 66, 69, 70, 75, 77, 78, 81, 84, 85, 87, 90, 91, 93, 95, 98, 99, 100, 102, 105, 108, 110, 111, 114, 115, 117, 119, 120, 121, 123, 125, 126, 129, 130, 132, 133, 135, 138, 140, 141, 143, 144, 145, 147, 150, 153
OFFSET
1,1
COMMENTS
Also indices of terms in A033676 that are not a power of 2.
Differs from A342082 in not having {24, 72, 80, 96, 112, ...}. - Hugo Pfoertner, Oct 15 2023
MATHEMATICA
A365408Q[n_]:=With[{d=Divisors[n]}, !IntegerQ[Log2[d[[Ceiling[Length[d]/2]]]]]];
Select[Range[200], A365408Q] (* Paolo Xausa, Oct 19 2023 *)
PROG
(Python)
from itertools import count, islice
from sympy import divisors
def A365408_gen(startvalue=1): # generator of terms >= startvalue
return filter(lambda i:(a:=(d:=divisors(i))[len(d)-1>>1])!=1<<a.bit_length()-1, count(max(startvalue, 1)))
A365408_list = list(islice(A365408_gen(), 30)) # Chai Wah Wu, Oct 18 2023
CROSSREFS
Complement of A365406.
Sequence in context: A235341 A356333 A342082 * A161345 A102655 A308748
KEYWORD
nonn
AUTHOR
Omar E. Pol, Oct 14 2023
STATUS
approved