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A344001
Indices k such that A011772(k) is odd.
4
1, 2, 4, 6, 8, 14, 15, 16, 20, 22, 24, 28, 30, 32, 33, 38, 40, 45, 46, 51, 52, 54, 60, 62, 63, 64, 65, 66, 69, 72, 77, 86, 87, 90, 91, 92, 94, 95, 96, 102, 112, 115, 116, 118, 120, 123, 124, 126, 128, 130, 134, 138, 140, 141, 142, 143, 144, 145, 148, 152, 153, 154, 156, 158, 159, 161
OFFSET
1,2
LINKS
PROG
(Python)
from sympy.ntheory.modular import crt
from sympy import factorint
from math import prod
from itertools import count, islice, combinations
def A344001_gen(): # generator of terms
for n in count(1):
plist = tuple(p**q for p, q in factorint(2*n).items())
if len(plist) == 1 or min(min(crt((m, 2*n//m), (0, -1))[0], crt((2*n//m, m), (0, -1))[0]) for m in (prod(d) for l in range(1, len(plist)//2+1) for d in combinations(plist, l))) & 1:
yield n
A344001_list = list(islice(A344001_gen(), 40)) # Chai Wah Wu, Jun 15 2022
CROSSREFS
Cf. A011772, A343999 (characteristic function), A344000 (complement).
Cf. also A354919.
Sequence in context: A086526 A086529 A054409 * A152973 A089747 A274170
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jun 01 2021
STATUS
approved