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%I #12 Jan 30 2023 07:39:52
%S 2,12,22,168,1558,5148,8062,177072,860882,738492,121008888,298775878,
%T 1232566932,14864798542,58374617952
%N a(n) = numerator of any non-diagonal entry of the matrix A^n, where A is described in the Comments lines.
%C A =
%C [ -3/5 -(2/5)i, -(2/5)i, -(2/5)i, -(2/5)i ]
%C [ -(2/5)i, -3/5 +(2/5)i, -(2/5)i, (2/5)i ]
%C [ -(2/5)i, -(2/5)i, -3/5 +(2/5)i, (2/5)i ]
%C [ -(2/5)i, (2/5)i, (2/5)i, -3/5 -(2/5)i ]
%C is the Cayley transform of the matrix iH, where H =
%C [1, 1, 1, 1]
%C [1, -1, 1, -1]
%C [1, 1, -1, -1]
%C [1, -1, -1, 1]
%C is a Hadamard matrix of order 4 and i is the imaginary unit.
%Y Cf. A066771.
%K nonn,frac,more
%O 1,1
%A _Simone Severini_, Apr 28 2004
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