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%I #4 May 24 2020 11:13:08
%S 9,15,105,112,609
%N Numbers n such that n! - 1 is divisible by a square greater than one.
%C Primes p such that p^2 divides m!-1 for some integer m<p see A152220.
%C a(6)=4929 [From _Artur Jasinski_, Nov 30 2008]
%t aa = {}; Do[If[(Sqrt[n! - 1] /. Sqrt[_] -> 1) > 1, Print[n]; AppendTo[aa, n], {n, 1, 1000}]; aa (*Artur Jasinski*)
%t nfdsQ[n_]:=AnyTrue[Rest[Divisors[n!-1]],IntegerQ[Sqrt[#]]&]; Select[Range[ 2,610],nfdsQ] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, May 24 2020 *)
%Y A064237
%K nonn
%O 1,1
%A _Artur Jasinski_, Nov 29 2008
%E Definition clarified by _Harvey P. Dale_, May 24 2020
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