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%I
%S 150401,13628801,136288001,113076743680001
%N Primes that are the concatenation 1, k! and 1, for some integer k.
%C Inspired by A089764.
%e For n = 1, k = 7, 7! = 5040, and a(1) = 150401 is a prime number.
%t Select[Table[FromDigits[Flatten[{(1), IntegerDigits[n!], {1}}]], {n, 1000}], PrimeQ] (* _Vincenzo Librandi_, Sep 15 2015 *)
%o (PARI) for(n=1, 1e3, if(isprime(k=eval(Str(1,n!,1))), print1(k", ")))
%o (MAGMA) [m: n in [1..1000] | IsPrime(m) where m is Seqint(Intseq(1) cat Intseq(Factorial(n)) cat Intseq(1))]; // _Vincenzo Librandi_, Sep 15 2015
%Y Cf. A089764.
%K nonn,hard,base
%O 1,1
%A _Altug Alkan_, Sep 14 2015
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