A203587 Vandermonde sequence using x^2 - xy + y^2 applied to (1,3,5,...,2n-1).
1, 7, 2793, 173302857, 3257420083394841, 30572436265385693946286383, 213701173947351299768327343802342830897, 1552400172652063971265258662606880393824188151866063025
Offset: 1
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