Let {n; b 2 , b 1 } denote the class of extended directed triple systems of the order n in which the number of blocks of the form [a, b, a] is b 2 and the number of blocks of the form [b, a, a] or [a, a, b] is b 1 . In this paper, we have shown that the necessary and sufficient condition for the existence of the class {n;
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