login
A344000
Indices k such that A011772(k) is even.
4
3, 5, 7, 9, 10, 11, 12, 13, 17, 18, 19, 21, 23, 25, 26, 27, 29, 31, 34, 35, 36, 37, 39, 41, 42, 43, 44, 47, 48, 49, 50, 53, 55, 56, 57, 58, 59, 61, 67, 68, 70, 71, 73, 74, 75, 76, 78, 79, 80, 81, 82, 83, 84, 85, 88, 89, 93, 97, 98, 99, 100, 101, 103, 104, 105, 106, 107, 108, 109, 110, 111, 113, 114, 117, 119
OFFSET
1,1
LINKS
PROG
(Python)
from sympy.ntheory.modular import crt
from sympy import factorint
from math import prod
from itertools import count, islice, combinations
def A344000_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 and 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 == 0:
yield n
A344000_list = list(islice(A344000_gen(), 40)) # Chai Wah Wu, Jun 15 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jun 01 2021
STATUS
approved