%I A118813
%S A118813 3628679,87178286159,20922789847679,265252859812191058635000805631999
%N A118813 Primes of the form (2n)! - n! - 1.
%C A118813 The next term is too large to include.
%C A118813 All the numbers end in 9
%e A118813 n=5 (2*5)! - 5! - 1 = 3628800 - 120 - 1 = 3628679
%p A118813 PFACT:=proc(N) local i,r; for i from 1 by 1 to N do r:=(2*i)!-i!-1; if 
               isprime(r) then print(i); fi; od; end: PFACT(100);
%Y A118813 Sequence in context: A107349 A053078 A116221 this_sequence A127229 A068158 
               A011521
%Y A118813 Adjacent sequences: A118810 A118811 A118812 this_sequence A118814 A118815 
               A118816
%K A118813 nonn
%O A118813 1,1
%A A118813 Paolo P. Lava and Giorgio Balzarotti (ppl(AT)spl.at), May 23 2006