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%I #8 Mar 07 2018 19:22:25
%S 1,7,9,13,13,9,16,1,9,1,7,9,13,13,9,16,10,9,1,7,9,13,13,9,16,10,9,10,
%T 16,9,13,13,9,16,1,9,10,16,9,13,13,9,16,10,9,1,16,9,13,13,9,16,10,9,1,
%U 16,9,13,13,9,16,10,18,10,16,9,13,13,9,16,1,9,10,16,9,13,13,9,16,1,9
%N Sum of digits of square of sum of digits of square.
%F a(n)=A004159(A004159(n))
%e a(2)=7 because sum of digits of square of 2 is 4 and sum of digits of square of 4 is 1+6=7
%t Array[Total[IntegerDigits[(Total[IntegerDigits[#^2]])^2]]&,90] (* _Harvey P. Dale_, Jan 17 2012 *)
%t Table[Nest[Total[IntegerDigits[#^2]]&,n,2],{n,90}] (* _Harvey P. Dale_, Mar 07 2018 *)
%Y Cf. A004159 for sum of digits of square, A056020 where iteration settles to 1, A056020 where iteration settles to 9, A056527 where iteration settles to 13 and 16. See also A056529.
%K base,easy,nonn
%O 1,2
%A _Henry Bottomley_, Jun 19 2000
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