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 A104768 Number of matrices G with entries in Z satisfying G^2=G+1 and having the form 2G=[1+p q-2n | q+2n 1-p]. 2

%I

%S 8,4,0,8,0,0,8,0,8,0,8,0,0,0,0,16,0,0,8,0,0,16,0,0,8,0,0,0,8,0,0,0,0,

%T 8,0,16,8,0,0,8,0,0,0,0,0,16,8,0,8,0,0,0,0,8,0,16,0,8,0,0,0,0,8,8,0,0,

%U 16,0,0,0,0,0,0,0,0,0,0,0,16,0,16,8,8,0,8,0,0,0,0,0,16,8,0,0,0,0,0,0,0,8,0

%N Number of matrices G with entries in Z satisfying G^2=G+1 and having the form 2G=[1+p q-2n | q+2n 1-p].

%C The matrix solutions to G^2=G+1 are gI, g'I (where g is the golden number and g'=1-g) and the matrices 2G=[1+p q-B | q+B 1-p]. It is easy to see that B must be even.

%F a(n)=8*104767(n) if n != 1, a(1)=4.

%Y Cf. A104767.

%K easy,nonn

%O 0,1

%A Michele Dondi (blazar(AT)lcm.mi.infn.it), Mar 24 2005

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Last modified September 20 13:45 EDT 2020. Contains 337264 sequences. (Running on oeis4.)