This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A081785 Continued cotangent for log(2). 0
 0, 1, 5, 55, 14187, 314681540, 254841004490568887, 116515298784769863036311841843812470, 16752745298264669840183664790312981823804061660537952218518280274360024 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS FORMULA 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)) PROG (PARI) b(n)=if(n<0, 0, bn[n]); bn=vector(100); 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)) CROSSREFS Cf. A001620, A002666, A002667. Sequence in context: A068666 A082780 A063855 * A144996 A129440 A045729 Adjacent sequences:  A081782 A081783 A081784 * A081786 A081787 A081788 KEYWORD nonn AUTHOR Benoit Cloitre, Apr 10 2003 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.