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Factorials of nonprime numbers.
1

%I #19 May 07 2023 18:35:05

%S 1,24,720,40320,362880,3628800,479001600,87178291200,1307674368000,

%T 20922789888000,6402373705728000,2432902008176640000,

%U 51090942171709440000,1124000727777607680000,620448401733239439360000

%N Factorials of nonprime numbers.

%H Harry J. Smith, <a href="/A062313/b062313.txt">Table of n, a(n) for n=1,...,100</a>

%t f[n_]:=(n+1)!/(n!+1); lst={1};Do[AppendTo[lst,Numerator[f[n]]],{n,3,3*4!}];Union@lst (* _Vladimir Joseph Stephan Orlovsky_, Oct 21 2009 *)

%t Table[If[PrimeQ[n],Nothing,n!],{n,30}] (* _Harvey P. Dale_, May 07 2023 *)

%o (PARI) for(n=1,30, if(!isprime(n), print1(n!, ", ")))

%o (PARI) { n=0; f=1; for (m=1, 200, f*=m; if (!isprime(m), write("b062313.txt", n++, " ", f); if (n==100, break)) ) } \\ _Harry J. Smith_, Aug 04 2009

%Y Cf. A002808.

%K easy,nonn

%O 1,2

%A _Jason Earls_, Jul 05 2001