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Skellam distribution.svg Skellam distribution probability mass function This is discrete function defined only for integral values of own Krishnavedala Octave source code exp mm besseli abs sqrt set 'defaultlinemarkersize' 'defaultlinelinewidth' plot 'd' 'd' 'd' 'd' xlim xlabel 'k' set gca 'xminortick' 'on' 'yminortick' 'on'