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Numbers whose squares remain squares when prepended with 4 and appended with 25 in base 10.
5

%I #13 Nov 23 2014 03:07:51

%S 1390,3055334,28638619086007684802380,296356838660564717696928980,

%T 296450546123962656267474730

%N Numbers whose squares remain squares when prepended with 4 and appended with 25 in base 10.

%C a(6) >= 10^50. - _Hiroaki Yamanouchi_, Nov 22 2014

%e 1390^2 = 1932100, 4193210025 = 64755^2.

%Y Cf. A249968, A249969, A249971.

%K nonn,base,more

%O 1,1

%A _Chai Wah Wu_, Nov 18 2014