A344000 Indices k such that A011772(k) is even.

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

Author

N. J. A. Sloane, Jun 01 2021

Keywords

• nonn

Links

• N. J. A. Sloane, Table of n, a(n) for n = 1..9196

Crossrefs

Cf. A011772, A343999, A344001.

Programs

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