%I #9 May 09 2015 17:32:46
%S 1,8,2,7,0,1,4,7,1,7,6,0,8,5,9,2,2,2,6,3,7,3,8,4,3,1,9,2,8,5,2,8,9,2,
%T 4,7,3,7,4,7,9,3,6,2,9,6,0,8,2,5,4,8,5,4,4,2,6,1,6,2,4,6,2,9,5,6,2,1,
%U 0,0,1,5,2,3,8,7,0,9,6,7,2,7,8,3,1,0,7,2,4,4,1,6,6,1,4,3,0,5,5,5,0
%N Decimal expansion of a nested radical: sqrt(1! + sqrt(2! + sqrt(3! + ...
%H Chai Wah Wu, <a href="/A099876/b099876.txt">Table of n, a(n) for n = 1..10000</a>
%H Popular Computing (Calabasas, CA), <a href="/A257352/a257352.pdf">The CSR Function</a>, Vol. 4 (No. 34, Jan 1976), pages PC34-10 to PC34-11. Annotated and scanned copy.
%e 1.82701471760859222637384319285...
%t RealDigits[Fold[Sqrt[#1 + #2] &, 0, Reverse[Range[100]!]], 10, 111][[1]]
%o (PARI) t=0:forstep(n=300,1,-1,t=sqrt(t+n!)):print(t) gives more than enough correct digits for the number given here.
%Y Cf. A072449, A099874.
%K cons,easy,nonn
%O 1,2
%A Mark Hudson (mrmarkhudson(AT)hotmail.com), Nov 02 2004