On the class of A1 numbers: Definition, numerical modeling, domain of existence and application

The relation A₁ = A_1--A₁₊ is exploited to advance the class of positive real numbers A₁ by means of the ones A_1- and A₁₊. The latter are defined with the help of the positive purely imaginary zeros of a complex Kummer function of specially picked out parameters. A method is elaborated for counting the numerical equivalents of A_1- and A₁₊ (of A₁). Tables and graphs illustrate the outcomes of computations. The limits of the existence domains of each of the three kinds of numbers are found, too. A formula for calculation of the differential phase shift produced by the circular waveguide with azimuthally magnetized ferrite which sustains normal TE₀₁ mode is suggested, employing the quantities A₁.