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A355305 Carmichael numbers ending in 5.

%I A355305 #22 Jul 26 2022 10:10:13
%S A355305 1105,2465,10585,62745,278545,449065,825265,1050985,2531845,3224065,
%T A355305 3664585,5632705,6054985,9582145,11119105,12945745,13187665,13992265,
%U A355305 15403285,21584305,22665505,28787185,31692805,36121345,37354465,39353665,40280065,41298985,47006785,60112885,67371265,74165065,84417985
%N A355305 Carmichael numbers ending in 5.
%H A355305 Amiram Eldar, <a href="/A355305/b355305.txt">Table of n, a(n) for n = 1..10000</a>
%H A355305 <a href="/index/Ca#Carmichael">Index entries for sequences related to Carmichael numbers</a>
%t A355305 Select[10*Range[0, 10^7] + 5, CompositeQ[#] && Divisible[# - 1, CarmichaelLambda[#]] &] (* _Amiram Eldar_, Jul 07 2022 *)
%o A355305 (PARI) Korselt(n) = my(f=factor(n)); for(i=1, #f[, 1], if(f[i, 2]>1||(n-1)%(f[i, 1]-1), return(0))); 1;
%o A355305 isok(n) = ((n%10)==5) && !isprime(n) && Korselt(n) && n>1; \\ _Michel Marcus_, Jul 07 2022; after A002997
%o A355305 (Python)
%o A355305 from itertools import islice
%o A355305 from sympy import factorint, nextprime
%o A355305 def A355305_gen(): # generator of terms
%o A355305     p, q = 3, 5
%o A355305     while True:
%o A355305         for n in range(p+2+(-p+3)%10, q, 10):
%o A355305             f = factorint(n)
%o A355305             if max(f.values()) == 1 and not any((n-1) % (p-1) for p in f):
%o A355305                 yield n
%o A355305         p, q = q, nextprime(q)
%o A355305 A355305_list = list(islice(A355305_gen(),10)) # _Chai Wah Wu_, Jul 24 2022
%Y A355305 Intersection of A002997 and A017329.
%Y A355305 Cf. A352970, A354609, A355307, A355309.
%K A355305 nonn,base
%O A355305 1,1
%A A355305 _Omar E. Pol_, Jul 03 2022