This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A109847 #14 Sep 22 2015 14:56:58
%S A109847 8,14,6,20,20,6,14,8,0,890,88,348,1118,1190,420,1328,1394,162,1520,
%T A109847 1580,546,154,1748,600,1850,1898,216,1988,2030,690,2108,2144,66,2210,
%U A109847 2240,252,2294,2318,780,2360,2378,798,2408,220,270,2438,2444,816,2450,2450
%N A109847 Least common multiple of n and its 9's complement.
%H A109847 Alois P. Heinz, <a href="/A109847/b109847.txt">Table of n, a(n) for n = 1..9999</a>
%e A109847 a(2)=14 because 7=9-2 and lcm(2,7)=14
%e A109847 a(9)=lcm(0,9)=0. a(10)=lcm(89,10)=890.
%p A109847 digs := proc(inp::integer) local resul,shiftinp : resul := 1 : shiftinp := iquo(inp,10) : while shiftinp > 0 do resul := resul+1 : shiftinp := iquo(shiftinp,10) : od : RETURN(resul) : end: nin := proc(inp::integer) RETURN(10^digs(inp)-1-inp) : end : for n from 1 to 40 do comp := nin(n) ; #print(n,comp,lcm(n,comp)) ; printf("%d,",lcm(n,comp)) ; od : # _R. J. Mathar_, Mar 27 2006
%p A109847 # second Maple program:
%p A109847 a:= n-> ilcm((10^length(n)-1-n), n):
%p A109847 seq(a(n), n=1..100); # _Alois P. Heinz_, Sep 22 2015
%t A109847 Array[LCM[#,10^IntegerLength[#]-1-#]&,50] (* _Harvey P. Dale_, Apr 17 2012 *)
%Y A109847 Cf. A109848, A084021.
%K A109847 base,easy,nonn
%O A109847 1,1
%A A109847 _Amarnath Murthy_, Jul 06 2005
%E A109847 Corrected and extended by _R. J. Mathar_, Mar 27 2006
%E A109847 More terms from _Joshua Zucker_, May 03 2006