This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A350711 #16 Mar 27 2022 22:58:07
%S A350711 1,2,7,11,27,63,177
%N A350711 The number of different values taken by the determinant of a square n X n matrix whose elements are 1 or i = sqrt(-1).
%e A350711 For n = 2 there are 2^(2*2) = A002416(2) = 16 square 2 X 2 matrices whose elements are 1 or i. Their determinants take 7 distinct values: 0, 2, -2, 1 + i, 1 - i, -1 + i, -1 - i. So a(2) = 7.
%t A350711 Join[{1, 2}, Table[With[{d = Union[Det /@ DeleteCases[Subsets[Tuples[{1, I}, n], {n}], {{__, 1}, __, {I, __} | {__, I}}]]}, Length[Union[d, -d, {0}]]], {n, 2, 6}]]
%Y A350711 Cf. A002416, A089472.
%K A350711 nonn,hard,more
%O A350711 0,2
%A A350711 _Vladimir Reshetnikov_, Mar 27 2022