A354163 Index of A354162(n) in A090252.

15, 29, 59, 63, 65, 121, 131, 193, 239, 241, 243, 255, 257, 265, 387, 479, 483, 487, 489, 515, 527, 529, 531, 775, 777, 959, 961, 967, 969, 977, 979, 1023, 1031, 1055, 1059, 1063, 1143, 1551, 1553, 1555, 1921, 1923, 1935, 1937, 1939, 1951, 1953, 1955, 1959, 1961, 2047, 2063, 2064, 2111, 2113, 2119, 2127, 2288, 3073, 3105, 3107, 3111, 3113, 3839

Offset: 1

Author

N. J. A. Sloane, May 30 2022

Keywords

• nonn

Crossrefs

Cf. A090252, A354159, A354160, A354161, A354162.

Programs

Python

from itertools import count, islice
from collections import deque
from math import gcd, lcm
from sympy import factorint
def A354163_gen(): # generator of terms
    aset, aqueue, c, b, f, i = {1}, deque([1]), 2, 1, True, 1
    while True:
        for m in count(c):
            if m not in aset and gcd(m,b) == 1:
                i += 1
                if m % 2 and len(fm := factorint(m)) == sum(fm.values()) == 2:
                    yield i
                aset.add(m)
                aqueue.append(m)
                if f: aqueue.popleft()
                b = lcm(*aqueue)
                f = not f
                while c in aset:
                    c += 1
                break
A354163_list = list(islice(A354163_gen(),25)) # Chai Wah Wu, May 31 2022