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A081783
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Continued cotangent for zeta(2)=Pi^2/6.
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0
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1, 4, 172, 181307, 241328833528, 824652019956267685427678, 768422457901766762303892554138930904416139509281, 2110688056630901907060877896737932376507936264268382076456539236145849709148481095915090382331184
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OFFSET
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0,2
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LINKS
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FORMULA
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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))
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PROG
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(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))
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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