OFFSET
1,6
COMMENTS
b(n)=x(n)+i*y(n) where x(n) and y(n) are integer sequences.
FORMULA
a(n)=Im(b(n)) where b(1)=b(2)=b(3)=b(4)=i and b(n)=(1+b(n-1)*b(n-2)*b(n-3))/b(n-4)
CROSSREFS
KEYWORD
sign
AUTHOR
Benoit Cloitre, Sep 17 2003
STATUS
approved