Narcissistic half-and-half power-sequence terraces for

A power-sequence terrace for Zn is a Zn terrace that can be partitioned into segments one of which contains merely the zero element of Zn whilst each other segment is either (a) a sequence of successive powers of an element of Zn, or (b) such a sequence multiplied throughout by a constant. If n is odd, a Zn terrace (a1,a2,…,an) is a narcissistic half-and-half terrace if ai−ai−1=an+2−i−an+1−i for i=2,3,…,(n+1)/2. Constructions are provided for narcissistic half-and-half power-sequence terraces for Zn with n=pqt where p and q are distinct odd primes and t is a positive integer. All the constructions are for terraces with as few segments as possible. Attention is restricted to constructions covering values of n with n=pqt and n<300; terraces are provided for all such values except n=189. Particularly elegant constructions are available for n=275.