A354162 Products of exactly two distinct odd primes in A090252, in order of appearance.

21, 55, 85, 57, 161, 319, 217, 481, 205, 731, 517, 159, 1121, 1403, 871, 355, 1241, 869, 2407, 1691, 413, 3007, 2323, 1391, 4033, 565, 5207, 2227, 5891, 6533, 4321, 453, 1007, 623, 4867, 2231, 6161, 2119, 11189, 6401, 12709, 7421, 2159, 9563, 8213, 1507, 15247, 9259, 4031, 12367, 597, 2869, 11183, 1561, 13393, 7099, 3611, 14213, 24823

Offset: 1

Author

N. J. A. Sloane, May 30 2022

Keywords

• nonn

Comments

Odd terms in A354160. - Chai Wah Wu, May 31 2022

Crossrefs

Cf. A090252, A354159, A354160, A354161, A354163.

Programs

Python

from itertools import count, islice
from collections import deque
from math import gcd, lcm
from sympy import factorint
def A354162_gen(): # generator of terms
    aset, aqueue, c, b, f = {1}, deque([1]), 2, 1, True
    while True:
        for m in count(c):
            if m not in aset and gcd(m,b) == 1:
                if m % 2 and len(fm := factorint(m)) == sum(fm.values()) == 2:
                    yield m
                aset.add(m)
                aqueue.append(m)
                if f: aqueue.popleft()
                b = lcm(*aqueue)
                f = not f
                while c in aset:
                    c += 1
                break
A354162_list = list(islice(A354162_gen(),25)) # Chai Wah Wu, May 31 2022