A355307 Carmichael numbers ending in 7.

46657, 126217, 748657, 1569457, 4909177, 9613297, 11972017, 40160737, 55462177, 65037817, 106041937, 161035057, 178451857, 193910977, 196358977, 311388337, 328573477, 338740417, 358940737, 403043257, 461502097, 499310197, 556450777, 569332177, 633639097, 784966297, 902645857, 981789337, 1125038377

Offset: 1

Author

Omar E. Pol, Jul 24 2022

Keywords

• nonn
• base

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000
• Index entries for sequences related to Carmichael numbers

Crossrefs

Intersection of A002997 and A017353.

Cf. A352970, A354609, A355305, A355309.

Programs

Mathematica

Select[10*Range[0, 10^7] + 7, CompositeQ[#] && Divisible[# - 1, CarmichaelLambda[#]] &] (* Amiram Eldar, Jul 24 2022 *)

Python

from itertools import count, islice
from sympy import factorint
def A355307_gen(): # generator of terms
    for n in count(7,10):
        f = factorint(n)
        if len(f) == sum(f.values()) > 1 and not any((n-1) % (p-1) for p in f):
            yield n
A355307_list = list(islice(A355307_gen(),5)) # Chai Wah Wu, Jul 25 2022