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%I #4 Mar 31 2012 14:39:53
%S 0,1,1,1,1,1,1,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,0,1,0,1,1,0,0,0,0,1,1,
%T 0,0,0,0,1,1,0,0,0,0,1,1,1,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,
%U 0,0,0,0,0,0,0,1,0,1
%N Spiro-Fibonacci differences, a(n) = difference of two previous terms that are nearest when terms arranged in a spiral.
%H N. Fernandez, <a href="http://www.borve.org/primeness/spirofib.html">Graphical representations of some Spiro-Fibonacci sequences</a>
%e Terms are written in square boxes radiating spirally (cf. Ulam prime spiral). a(0)=0 and a(1)=1, so write 0 and then 1 to its right. a(2) goes in the box below a(1). The nearest two filled boxes contain a(0) and a(1), so a(2)=abs(a(0)-a(1))=abs(0-1)=1. a(3) goes in the box to the left of a(2). The nearest two filled boxes contain a(0) and a(2), so a(3)=abs(a(0)-a(2))=abs(0-1)=1.
%Y Cf. A063826, A078510.
%K nonn
%O 0,1
%A _Neil Fernandez_, Jan 07 2003
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