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a(n)^2 is the start of the first occurrence of n consecutive perfect powers, all of which are squares with exponents equal to 2 (A111245).
4

%I #5 Jan 18 2021 18:36:48

%S 2,6,12,19,37,65,104,133,173,263,375,408,561,689,854,1107,1348,1534,

%T 1819,2062,2415,2871,3308,3695,4241,4837,5353,5995,6576,7291,8211,

%U 8979,9866,10880,11995,12934,14113,15326,16572,17889,19159,20663,22289,23869,25750,27361

%N a(n)^2 is the start of the first occurrence of n consecutive perfect powers, all of which are squares with exponents equal to 2 (A111245).

%F a(n) = sqrt(A340661(n)).

%e See A340661.

%Y Cf. A000290, A001597, A111245, A340661, A340662, A340664, A340695.

%K nonn

%O 1,1

%A _Hugo Pfoertner_, Jan 18 2021