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A068810
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.
1
1, 9, 36, 64, 100, 324, 676, 900, 3600, 6400, 9216, 10000, 32400, 67600, 90000, 99856, 123904, 360000, 640000, 876096, 921600, 1000000, 3240000, 3968064, 6031936, 6760000, 9000000, 9985600, 12390400, 28901376, 36000000, 64000000
OFFSET
1,2
COMMENTS
Terms from V. P. Singh. If k in sequence so is k * 100^m. See A068075 for the smaller of the primitive pairs.
EXAMPLE
324 = 18^2 is a member as 1000 - 324 = 676 = 26^2.
MATHEMATICA
Select[Range[10^4]^2, IntegerQ[Sqrt[10^(IntegerLength[#]) - #]] &] (* Jayanta Basu, Aug 05 2013 *)
CROSSREFS
Cf. A068075.
Sequence in context: A169580 A258844 A294952 * A077115 A297584 A073946
KEYWORD
nonn,base
AUTHOR
Amarnath Murthy, Mar 07 2002
EXTENSIONS
Edited and extended by Robert G. Wilson v, Mar 20 2002
STATUS
approved