%I A118812
%S A118812 2,23,87178286161,403291461126605629356979201,
%T A118812 5502622159812088949850305428800254867109635014075023360001
%N A118812 Primes of the form (2n)! - n! + 1.
%e A118812 n=2 (2*2)! - 2! + 1 = 24 - 2 + 1 = 23
%p A118812 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 A118812 Sequence in context: A067837 A089987 A162605 this_sequence A054909 A100816 
               A079612
%Y A118812 Adjacent sequences: A118809 A118810 A118811 this_sequence A118813 A118814 
               A118815
%K A118812 nonn
%O A118812 1,1
%A A118812 Paolo P. Lava & Giorgio Balzarotti (ppl(AT)spl.at), May 23 2006