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A180737
a(n) is the largest n-digit square whose sum of digits is also a square.
2
9, 81, 961, 9025, 96721, 990025, 9966649, 99980001, 999761161, 9999400009, 99998250625, 999946000729, 9999989500176, 99999960000004, 999999455981824, 9999998600000049, 99999998724439696, 999999998000000001
OFFSET
1,1
LINKS
MATHEMATICA
lnds[n_]:=Module[{s=Floor[Sqrt[10^n-1]]}, While[!IntegerQ[Sqrt[Total[ IntegerDigits[ s^2]]]], s--]; s^2]; Array[lnds, 20] (* Harvey P. Dale, Mar 28 2013 *)
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Daniel Mondot, Oct 08 2010
STATUS
approved