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A301514 Infinite nested radical negated: i*sqrt(1+2i*sqrt(1+3i*sqrt(1+4i*sqrt(1+5i*sqrt(1+...))))).

%I A301514 #35 Dec 28 2018 04:20:32
%S A301514 2,4,9,4,6,2,5,1,4,7,5,4,1,0,0,9,2,9,0,1,8,7,2,2,7,1,3,0,0,0,4,0,7,7,
%T A301514 4,5,1,2,6,8,7,7,3,3,6,6,7,0,8,4,1,3,9,6,1,4,7,5,5,9,2,3,0,0,4,4,3,4,
%U A301514 3,3,9,6,4,9,9,1,2,2,0,9,9,2,5,3,2,8,2,9,3,2,1,4,9,6,5,0,9,7,8,9,3,0,1,2,6
%N A301514 Infinite nested radical negated: i*sqrt(1+2i*sqrt(1+3i*sqrt(1+4i*sqrt(1+5i*sqrt(1+...))))).
%C A301514 Inspired by Ramanujan's infinite nested radical of natural numbers.
%D A301514 Ramanujan's 2nd Notebook, Chapter XII, Page 108, entry 4.
%H A301514 Robert G. Wilson v, <a href="/A301514/b301514.txt">Table of n, a(n) for n = 1..10001</a>
%e A301514 2.4946251475410092901872271300040774512687733667084139614755923004434339649...
%t A301514 RealDigits[Chop[N[-I*Fold[#2*Sqrt[1 + #1*I] &, 0, Reverse[Range[400]]], 125]], 10, 120][[1]] (* _Vaclav Kotesovec_, Dec 22 2018 *)
%o A301514 (PARI)
%o A301514 b(n) = imag(fold((x,y)->sqrt(1+x*y), Vecrev([2..n+1])*I));
%o A301514 N=106; default(realprecision, N); limitnum(b,,4) \\ _Gheorghe Coserea_, Dec 23 2018
%Y A301514 Cf. A072449, A239349.
%K A301514 cons,nonn
%O A301514 1,1
%A A301514 _Robert G. Wilson v_, Dec 15 2018