=SI(COLONNES($G:G)<=SOMME(1/NB.SI($A$4:$A$31;$A$4:$A$31))*2;INDEX($A$4:$A$31;PETITE.VALEUR(SI(LIGNE(INDIRECT("1:"&LIGNES($A$4:$A$31)))=EQUIV($A$4:$A$31;$A$4:$A$31;0);EQUIV($A$4:$A$31;$A$4:$A$31;0));MOD(ENT((COLONNES($G:G)-1)/2);LIGNES($A$4:$A$31))+1));"")