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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
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, 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, 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
OFFSET
0,1
COMMENTS
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.
FORMULA
a(n)=8*104767(n) if n != 1, a(1)=4.
CROSSREFS
Cf. A104767.
Sequence in context: A096616 A151558 A103613 * A199430 A228497 A199285
KEYWORD
easy,nonn
AUTHOR
Michele Dondi (blazar(AT)lcm.mi.infn.it), Mar 24 2005
STATUS
approved