...factorial(n) plus/minus 1 is semiprime
Is there an Oeis sequence dedicated to numbers n such that n!+1 and n!1 are both semiprime? An example is 20970
Infact 20970!+1 is semiprime and also 20970!1 is semi prime
No the example is wrong
Last fiddled with by enzocreti on 20200901 at 08:46
