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%I #11 Jan 24 2016 19:43:55
%S 9,8,7,6,5,4,3,2,1,0,98,88,78,68,58,48,38,28,18,8,97,87,77,67,57,47,
%T 37,27,17,7,96,86,76,66,56,46,36,26,16,6,95,85,75,65,55,45,35,25,15,5,
%U 94,84,74,64,54,44,34,24,14,4,93,83,73,63,53,43,33,23,13
%N Complement obverse of n.
%C Replace digits of n by their 9's complements, reverse the order, omit any leading zeros.
%C Suggested by a posting by Mike Stay to the Math Fun Mailing List, Jan 24 2016, which in turn was loosely based on the definition used in logic (see the Philosophy Pages link).
%H Alois P. Heinz, <a href="/A267193/b267193.txt">Table of n, a(n) for n = 0..9999</a>
%H Garth Kemerling, <a href="http://www.philosophypages.com/lg/e07b.htm">Philosophy Pages: Immediate Inferences</a>.
%e The 9's complement of the digits of 980 are 019, so a(980) = 910.
%p a:= n-> (s-> parse(cat(seq(9-s[i], i=1..nops(s))))
%p )(convert(n, base, 10)):
%p seq(a(n), n=0..100); # _Alois P. Heinz_, Jan 24 2016
%Y Cf. A061601 (9's complement of n).
%K nonn,base
%O 0,1
%A _N. J. A. Sloane_, Jan 24 2016
%E More terms from _Alois P. Heinz_, Jan 24 2016