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A355307 Carmichael numbers ending in 7.

%I A355307 #24 Jul 25 2022 15:41:37
%S A355307 46657,126217,748657,1569457,4909177,9613297,11972017,40160737,
%T A355307 55462177,65037817,106041937,161035057,178451857,193910977,196358977,
%U A355307 311388337,328573477,338740417,358940737,403043257,461502097,499310197,556450777,569332177,633639097,784966297,902645857,981789337,1125038377
%N A355307 Carmichael numbers ending in 7.
%H A355307 Amiram Eldar, <a href="/A355307/b355307.txt">Table of n, a(n) for n = 1..10000</a>
%H A355307 <a href="/index/Ca#Carmichael">Index entries for sequences related to Carmichael numbers</a>
%t A355307 Select[10*Range[0, 10^7] + 7, CompositeQ[#] && Divisible[# - 1, CarmichaelLambda[#]] &] (* _Amiram Eldar_, Jul 24 2022 *)
%o A355307 (Python)
%o A355307 from itertools import count, islice
%o A355307 from sympy import factorint
%o A355307 def A355307_gen(): # generator of terms
%o A355307     for n in count(7,10):
%o A355307         f = factorint(n)
%o A355307         if len(f) == sum(f.values()) > 1 and not any((n-1) % (p-1) for p in f):
%o A355307             yield n
%o A355307 A355307_list = list(islice(A355307_gen(),5)) # _Chai Wah Wu_, Jul 25 2022
%Y A355307 Intersection of A002997 and A017353.
%Y A355307 Cf. A352970, A354609, A355305, A355309.
%K A355307 nonn,base
%O A355307 1,1
%A A355307 _Omar E. Pol_, Jul 24 2022