Outer

Outer[f,list1,list2,…] gives the generalized outer product of the listi, forming all possible combinations of the lowest‐level elements in each of them, and feeding them as arguments to f. 

Outer[f,list1,list2,…,n] treats as separate elements only sublists at level n in the listi. 

Outer[f,list1,list2,…,n1,n2,…] treats as separate elements only sublists at level ni in the corresponding listi. 

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