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a(n) is root of square starting with digit 7: first term of runs.
2

%I #11 Oct 08 2019 16:29:01

%S 27,84,265,837,2646,8367,26458,83667,264576,836661,2645752,8366601,

%T 26457514,83666003,264575132,836660027,2645751312,8366600266,

%U 26457513111,83666002654,264575131107,836660026535,2645751311065

%N a(n) is root of square starting with digit 7: first term of runs.

%F a(n) = ceiling(sqrt(7*10^n)), n > 1.

%t Ceiling[Sqrt[7*10^Range[2,30]]] (* _Harvey P. Dale_, Jan 21 2015 *)

%Y Cf. A067477 (squares), A035076 (2..9).

%K nonn,base

%O 2,1

%A _Patrick De Geest_, Nov 15 1998