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 A199045 #10 Jul 13 2013 12:04:18 %S A199045 2,12,112,1120,10112,101120,1002112,10010112,100101120,1001011200, %T A199045 10002010112,100012122112,1000121221120,10001212211200, %U A199045 100002002010112,1000000210010112,10000002100101120,100000021001011200,1000000210010112000,10000000201221210112 %N A199045 Smallest multiple of 2^n having in decimal representation exactly n digits <= 2. %C A199045 A050621(n) <= a(n) < A050621(n+1); A054055(a(n)) <= 2. %H A199045 Reinhard Zumkeller, <a href="/A199045/b199045.txt">Table of n, a(n) for n = 1..32</a> %e A199045 n=3: A050621(3) = 104 = 8 * 13, a(3) = 112 = 8 * 14; %e A199045 n=4: A050621(4) = 1008 = 16 * 63, a(4) = 1120 = 16 * 70. %o A199045 (Haskell) %o A199045 a199045 n = head $ %o A199045 filter ((<= 2) . a054055) $ map (* 2^n) [a034478 (n-1)..] %Y A199045 Cf. A000079, A034478, A159952. %K A199045 nonn,base %O A199045 1,1 %A A199045 _Reinhard Zumkeller_, Nov 02 2011