分布函数
Gamma function

http://pass2.tk/index.php?q=YUhSMGNEb3ZMMlZ1TG5kcGEybHdaV1JwWVM1dmNtY3ZkMmxyYVM5SFlXMXRZVjltZFc1amRHbHZiZz09&degree0.09521019132807851

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