|
Search: id:A081783
|
|
|
| A081783 |
|
Continued cotangent for zeta(2)=Pi^2/6. |
|
+0
1
|
|
| 1, 4, 172, 181307, 241328833528, 824652019956267685427678, 768422457901766762303892554138930904416139509281, 2110688056630901907060877896737932376507936264268382076456539236145849709148481095915090382331184
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
FORMULA
|
Pi^2/6=cot(sum(n>=0, n, (-1)^n*acot(a(n))); let b(0)=Pi^2/6, b(n)=(b(n-1)*floor(b(n-1))+1)/(b(n-1)-floor(b(n-1)) then a(n)=floor(b(n))
|
|
PROGRAM
|
(PARI) ?bn=vector(100); b(n)=if(n<0, 0, bn[n]); bn[1]=Pi^2/6; ?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: A017414 A051476 A057140 this_sequence A006433 A113254 A127606
Adjacent sequences: A081780 A081781 A081782 this_sequence A081784 A081785 A081786
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Benoit Cloitre (benoit7848c(AT)orange.fr), Apr 10 2003
|
|
|
Search completed in 0.002 seconds
|
