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- #!/usr/bin/ruby
- # Formula due to Krzysztof Maslanka
- func Ak(k) {
- sum(0..k, {|j|
- (-1)**j * binomial(k, j) * (2*j + 1) * zeta(2*j + 2)
- })
- }
- func krzysztof_zeta(s, r=100) {
- sum(0..r, {|k|
- (gamma(k + 1 - s/2) / gamma(1 - s/2)) * (Ak(k) / k!)
- }) / (s - 1)
- }
- say krzysztof_zeta(3) #=> 1.2020569022705898699637409727804911671219286162
- say krzysztof_zeta(5) #=> 1.0369277551507417486201175962997774385468699839
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