%I #11 Dec 20 2012 16:52:49
%S 1,1,8,8,8,8,8,1,8,8,1,8,8,1,8,8,8,8,8,1,8,8,8,1,8,8,8,8,1,8,8,1,1,8,
%T 8,8,8,8,8,8,8,8,8,8,1,8,8,8,8,1,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
%U 1,8,1,8,8,8,8,8,8,8,8,1,8,8,1,8,8,8,1,8,8,8,8,1,8,8,1,8,8,1,8,8
%N Periods of sum of squares of digits iterated until the sequence becomes periodic.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Digitaddition.html">Digit addition.</a>
%Y Cf. A003132, A099645. [From _R. J. Mathar_, May 31 2009]
%K nonn,base
%O 0,3
%A _Eric W. Weisstein_
%E The value a(0)=1 was added by _R. J. Mathar_, May 31 2009