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 A093378 a(n) = numerator of any non-diagonal entry of the matrix A^n, where A is described in the Comments lines. 1

%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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Last modified June 4 03:55 EDT 2023. Contains 363118 sequences. (Running on oeis4.)