Function

Logan

Valko

Stehfest

Salzer-Gaver

$\tau$

$\tau$

$\tau$

$\tau$

2

0.89

1.44

0.43

2.37

8

0.55

0.88

0.41

3.06

11

0.94

3.87

1.74

2.56

13

0.72

0.94

0.41

0.99

18

0.56

1.05

0.52

1.27