%I A084830
%S A084830 2,3,4,5,6,14,17,50,111,254,506
%N A084830 Numbers n such that (n!)^2 + n! - 1 is prime.
%D A084830 H. Dubner, Factorial and primorial primes, J. Rec. Math., 19 (No. 3, 
               1987).
%e A084830 5 is in the sequence because (5!)^2+5!-1=14519 is prime.
%t A084830 Do[If[PrimeQ[n!^2+n!-1], Print[n]], {n, 600}]
%Y A084830 Cf. A002981, A002982.
%Y A084830 Sequence in context: A046063 A065638 A039016 this_sequence A116044 A116027 
               A085157
%Y A084830 Adjacent sequences: A084827 A084828 A084829 this_sequence A084831 A084832 
               A084833
%K A084830 more,nonn
%O A084830 1,1
%A A084830 Farideh Firoozbakht (f.firoozbakht(AT)sci.ui.ac.ir), Jul 12 2003