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%I #5 Mar 30 2012 17:36:38
%S 1,2,5,18,63
%N (n! + 1) == 0 ( mod prime(n) ).
%t Do[ If[ Mod[n! + 1, Prime[n]] == 0, Print[n]], {n, 1, 10000} ]
%o (PARI) for(X=10001,33333,if( (X!+1)%prime(X)==0, print(X)))
%Y Cf. A067999, A066953.
%K nonn,hard
%O 1,2
%A _Robert G. Wilson v_, Feb 08 2002
%E There are no other terms below 33333. Is 63 the last term? - Hauke Worpel (hw1(AT)email.com), May 24 2003
%E There are no other terms below 534000. - _Rick L. Shepherd_, May 26 2003