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%I #12 Aug 19 2019 02:58:46
%S 9,16,21,24,25,24,21,16,9,900,979,1056,1131,1204,1275,1344,1411,1476,
%T 1539,1600,1659,1716,1771,1824,1875,1924,1971,2016,2059,2100,2139,
%U 2176,2211,2244,2275,2304,2331,2356,2379
%N a(n) = n*c(n), where c(n) is the 10's complement of n.
%H Robert Israel, <a href="/A068824/b068824.txt">Table of n, a(n) for n = 1..10000</a>
%F G.f.: -2*x^2/(1-x)^3 + (9/(1-x)^2)*Sum_{k=0..infinity} (10^(2*d)*x^(10^d)-(10^(2*d)-10^d)*x^(1+10^d)). - _Robert Israel_, Aug 18 2019
%e a(45) = 2475 as 10's complement of 45 is 100-45 = 55 and 45*55 = 2475.
%p seq((10^(1+ilog10(n))-n)*n, n=1..100); # _Robert Israel_, Aug 18 2019
%t #*(10^(IntegerLength[#]) - #) & /@ Range[39] (* _Jayanta Basu_, Aug 07 2013 *)
%K easy,nonn,base
%O 1,1
%A _Amarnath Murthy_, Mar 08 2002