The Poisson-Charlier polynomials form a Sheffer sequence with
(1)
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(2)
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giving the generating function
(3)
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The Sheffer identity is
(4)
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where is a falling factorial (Roman 1984, p. 121). The polynomials satisfy the recurrence relation
(5)
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These polynomials belong to the distribution where is a step function with jump
(6)
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at , 1, ... for . They are given by the formulas
(7)
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(8)
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(9)
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(10)
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(11)
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where is a binomial coefficient, is a falling factorial, is an associated Laguerre polynomial, is a Stirling number of the first kind, and
(12)
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(13)
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They are normalized so that
(14)
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where is the delta function.
The first few polynomials are
(15)
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(16)
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(17)
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(18)
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