Negative Binomial Distribution PDF Calculator

For a negative binomial distribution (defined as the number of failures \( x \) before the \( r \)th success) with success probability \( p \), the PDF (or PMF) is: $$ P(X=x)=\binom{x+r-1}{x}(1-p)^r p^x,\quad x=0,1,2,\dots $$

* Enter the failure count \( x \) (nonnegative integer), the number of successes \( r \) (positive integer), and the success probability \( p \) (with \( 0