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%I #6 Nov 28 2024 21:21:22
%S 2,19,3628789,479001587
%N Primes of the form n! - n - 1.
%C a(5), a 730-digit number, has been certified prime with Primo.
%F a(k) = A073443(k)! - A073443(k) - 1.
%e a(1) = 4! - 4 - 1 = 19, a prime, so 19 is in this sequence (4 = A073443(1)).
%o (PARI) for(n=3,2000, p=n!-n-1; if(isprime(p),print1(p,",")))
%Y Cf. A073443 (corresponding n).
%K nonn
%O 1,1
%A _Rick L. Shepherd_, Jul 31 2002