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A109910 a(n) = 9's complement of digit reversal of n.

%I A109910 #23 Dec 31 2024 15:39:18
%S A109910 9,8,7,6,5,4,3,2,1,0,8,88,78,68,58,48,38,28,18,8,7,87,77,67,57,47,37,
%T A109910 27,17,7,6,86,76,66,56,46,36,26,16,6,5,85,75,65,55,45,35,25,15,5,4,84,
%U A109910 74,64,54,44,34,24,14,4,3,83,73,63,53,43,33,23,13,3,2
%N A109910 a(n) = 9's complement of digit reversal of n.
%H A109910 Nathaniel Johnston, <a href="/A109910/b109910.txt">Table of n, a(n) for n = 0..10000</a>
%F A109910 a(n) = A061601(A004086(n)). - _Indranil Ghosh_, Jan 30 2017
%e A109910 a(17) = 28. Digit reversal of 17 = 71, 9's complement of 71 is 99-71 = 28.
%p A109910 R := proc(n) local nn, nnn: nn:=convert(n, base, 10): add(nn[nops(nn)+1-j]*10^(j-1), j=1..nops(nn)): end:
%p A109910 A109910 := proc(n) return 10^length(max(R(n),1)) - R(n) - 1: end:
%p A109910 seq(A109910(n),n=0..70); # _Nathaniel Johnston_, Apr 28 2011
%t A109910 Table[10^If[# == 0, 1, IntegerLength@ #] - 1 - # &@ FromDigits@ Reverse@ IntegerDigits@ n, {n, 0, 70}] (* _Michael De Vlieger_, Feb 01 2017 *)
%o A109910 (Python)
%o A109910 def A109910(n):
%o A109910     x=int(str(n)[::-1])
%o A109910     return 10**len(str(x))-1-x # _Indranil Ghosh_, Jan 30 2017
%Y A109910 Cf. A004086, A061601, A109911.
%K A109910 base,easy,nonn,look
%O A109910 0,1
%A A109910 _Amarnath Murthy_, Jul 16 2005