B2⁢n⁡(x)=(-1)n+1⁢2⁢n⁢∫0∞cos⁡(2⁢π⁢x)-ⅇ-2⁢π⁢tcosh⁡(2⁢π⁢t)-cos⁡(2⁢π⁢x)⁢t2⁢n-1⁢ⅆ⁡t,