|
%I
%S 0,1,5,55,14187,314681540,254841004490568887,
%T 116515298784769863036311841843812470,
%U 16752745298264669840183664790312981823804061660537952218518280274360024
%N Continued cotangent for log(2).
%F log(2)=cot(sum(n>=0, n, (-1)^n*acot(a(n))); let b(0)=log(2), b(n)=(b(n-1)*floor(b(n-1))+1)/(b(n-1)-floor(b(n-1)) then a(n)=floor(b(n))
%o (PARI) ?bn=vector(100); b(n)=if(n<0,0,bn[n]); bn[1]=log(2); ?for(n=2,10,bn[n]=(b(n-1)*floor(b(n-1))+1)/(b(n-1)-floor(b(n-1)))) ?a(n)=floor(b(n+1))
%Y Cf. A001620, A002666, A002667.
%K nonn
%O 0,3
%A _Benoit Cloitre_, Apr 10 2003
|
