%I #10 May 04 2018 08:46:52
%S 2,4,0,1,9,3,4,7,2,7,1,3,5,4,0,4,0,2,9,0,7,6,5,9,9,0,1,6,5,3,6,1,9,4,
%T 3,8,8,0,4,8,6,9,9,0,4,0,2,1,9,5,4,7,6,0,5,7,1,4,1,4,2,4,6,1,1,2,5,6,
%U 7,5,3,0,8,5,7,8,9,9,3,9,6,7,0,7,4,4,3,5,3,6,8,9,7,2,0,5,4,0,4,0,4,9,9,4,4
%N Decimal expansion of continued fraction 1/(4+1/(6+1/(8+1/(9+1/(10+...))))).
%C Decimal expansion of the constant whose continued fraction form is the sequence of all the composite numbers.
%e 0.24019347271354040290765990165361943880486990402195476057141424611256753...
%p with(numtheory); P:=proc(q) local a,n; a:=0; for n from q by -1 to 4 do if not isprime(n) then a:=1/(a+n); fi; od; print(evalf(a,120)); end: P(10^4);
%t RealDigits[ Fold[1/(#1 + #2) &, 1, Reverse[ Composite@# & /@ Range@40]], 10, 111][[1]] (* _Robert G. Wilson v_, Apr 29 2018 *)
%Y Cf. A002808, A084255.
%K nonn,easy,cons
%O 0,1
%A _Paolo P. Lava_, Apr 16 2018