Digital Library of Mathematical Functions
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6 Exponential, Logarithmic, Sine, and Cosine IntegralsProperties

§6.9 Continued Fraction

6.9.1 E1(z)=-zz+11+1z+21+2z+31+3z+,
|phz|<π.

See also Cuyt et al. (2008, pp. 287–290).