Devarim 33:6

יחי ראובן LET REUBEN LIVE, in this world, ואל ימת AND LET HIM NOT DIE, in the world to come (Sifrei Devarim 347:1) : that the incident of Bilhah be not remembered unto him (Sifrei Devarim 347:3). ויהי מתיו מספר lit., AND LET HIS MEN BE A NUMBER — let him be counted amongst the number of his other brothers. This is exactly similar to the idea that is expressed in the text, (Genesis 35:22) “[And Reuben went] and lay with Bilhah [his father’s wife]” … “And the sons of Jacob were twelve”, which suggests that he was not excluded from the number of Jacob’s sons.

יְחִ֥י רְאוּבֵ֖ן וְאַל־יָמֹ֑ת וִיהִ֥י מְתָ֖יו מִסְפָּֽר׃ {ס}        

Let Re᾽uven live, and not die; and let not his men be few.