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a(n) = smallest number m such that decimal expansion of m^2 has exactly (n+1) digits n.
0

%I #2 Mar 30 2012 17:26:35

%S 0,11,149,1156,2538,22925,163284,2116076,9321378,31622764

%N a(n) = smallest number m such that decimal expansion of m^2 has exactly (n+1) digits n.

%e a(0)=0 because 0^2=0 has one 0

%e a(1)=1 because 11^2=121 has two 1's

%e a(2)=149 because 149^2=22201 has three 2's

%e a(8)=9321378 because 9321378^2=86888087818884 has nine 8's

%e a(9)=31622764 because 31622764^2=999999202999696 has ten 9's.

%Y Cf. A086935, A179895.

%K base,fini,full,nonn

%O 0,2

%A _Zak Seidov_, Aug 01 2010