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%I #4 Mar 30 2012 17:35:07
%S 1,8,12,8,11,16,5,12,11,1,9,12,2,13,10,8,12,12,4,8,11,13,3,8,10,12,13,
%T 3,9,13,2,3,12,11,12,15,8,9,13,8,13,8,11,4,14,11,11,13,4,11,10,10,12,
%U 14,12
%N a(n) = length of period of transformation sum-digit-square: given a number m(k) define m(k+1) to be the sum of the squares of the decimal digits of m(k) and iterate until m(s) is found such that m(s)=m(k) with k<s. Numbers repeat periodically with a period of length a(n).
%D C. Suriano, Miniature Matematiche, unpublished, 2009, section 30
%e a(1)=1 since 1^2=1; a(2)=8 since the period contains 8 numbers: 4,16,37,58,89,145,42,20 the following being 4 again.
%e a(5)=11 since the sequence runs as follows:
%e 25,29, 85, 89, 145, 42, 20, 4, 16, 37, 58 the next term being 89 that is already there.
%Y Cf. A152077.
%K nonn,base
%O 1,2
%A _Carmine Suriano_, May 29 2009
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