The OEIS is supported by the many generous donors to the OEIS Foundation.
%I #13 Jan 16 2018 02:43:56
%S 1,9,36,64,100,324,676,900,3600,6400,9216,10000,32400,67600,90000,
%T 99856,123904,360000,640000,876096,921600,1000000,3240000,3968064,
%U 6031936,6760000,9000000,9985600,12390400,28901376,36000000,64000000
%N Numbers n such that n and its 10's complement are both squares, i.e., n and 10^k - n (where k is the number of digits in n) are squares.
%C Terms from V. P. Singh. If k in sequence so is k * 100^m. See A068075 for the smaller of the primitive pairs.
%e 324 = 18^2 is a member as 1000 - 324 = 676 = 26^2.
%t Select[Range[10^4]^2, IntegerQ[Sqrt[10^(IntegerLength[#]) - #]] &] (* _Jayanta Basu_, Aug 05 2013 *)
%Y Cf. A068075.
%K nonn,base
%O 1,2
%A _Amarnath Murthy_, Mar 07 2002
%E Edited and extended by _Robert G. Wilson v_, Mar 20 2002