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A076379 n!-x!+1 is never prime for x<n. 1

%I #5 Sep 12 2022 19:21:34

%S 1,15,22,27,28,36,43,45,48,50,52,58,60,63,64,67,70,77,80,82,83,84,85,

%T 86,97,104,110,113,120,124,125,129,131,135,136,138,140,147,158,161,

%U 164,171,173,174,183,185,189,192,195,199

%N n!-x!+1 is never prime for x<n.

%t Select[Range[200],NoneTrue[Table[#!-x!+1,{x,#-1}],PrimeQ]&] (* _Harvey P. Dale_, Sep 12 2022 *)

%o (PARI) for (a=1,100,c=0; for (b=1,a-1, if (b%2<>a%2,continue); if (isprime(a!-b!+1),c=1; break)); if (c==0,print1(a,",")))

%Y Cf. A076378.

%K nonn

%O 1,2

%A _Jon Perry_, Oct 08 2002

%E More terms from _Harvey P. Dale_, Sep 12 2022

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Last modified April 24 20:08 EDT 2024. Contains 371963 sequences. (Running on oeis4.)