%I #8 Aug 18 2019 01:44:31
%S 99,96,91,84,75,64,51,36,19,9900,9879,9856,9831,9804,9775,9744,9711,
%T 9676,9639,9600,9559,9516,9471,9424,9375,9324,9271,9216,9159,9100,
%U 9039,8976,8911,8844,8775,8704,8631,8556,8479,8400,8319,8236,8151,8064,7975
%N a(n) = (10^k - n)(10^k + n), where k is the number of digits in n.
%H Harvey P. Dale, <a href="/A110397/b110397.txt">Table of n, a(n) for n = 1..1000</a>
%e a(3)=(10-3)(10+3)=91; a(11)=(100+11)(100-11)=111*89=9879.
%p s:=proc(m) nops(convert(m,base,10)) end: a:=n->(10^(s(n))-n)*(10^(s(n))+n): seq(a(n),n=1..55); # s gives number of digits # _Emeric Deutsch_, Aug 01 2005
%t Table[Times@@(10^IntegerLength[n]+{n,-n}),{n,50}] (* _Harvey P. Dale_, May 31 2015 *)
%K base,easy,nonn
%O 1,1
%A _Amarnath Murthy_, Jul 29 2005
%E More terms from _Emeric Deutsch_, Aug 01 2005
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