%I #7 Dec 05 2013 19:55:06
%S 1,121,12621,12624621,1262412024621,1262412072012024621,
%T 12624120720504072012024621,12624120720504040320504072012024621,
%U 1262412072050404032036288040320504072012024621,12624120720504040320362880362880036288040320504072012024621
%N Concatenation of factorials in increasing order up to the n-th and then in decreasing order.
%t fr[n_]:=Module[{f=Factorial[Range[n]]},FromDigits[Flatten[ IntegerDigits/@ Join[ f,Reverse[ Most[f]]]]]]; Array[fr,10] (* _Harvey P. Dale_, Oct 21 2013 *)
%K easy,nonn,base
%O 1,2
%A _Amarnath Murthy_, Dec 25 2001
%E More terms from _Sascha Kurz_, Mar 23 2002
%E One more term from _Harvey P. Dale_, Oct 21 2013