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 A073646 #16 Jan 27 2014 12:29:45
%S A073646 1,2,3,22,5,23,7,222,33,25,11,223,13,27,35,2222,17,233,19,225,37,112,
%T A073646 23,2223,55,132,333,227,29,235,31,22222,113,172,57,2233,37,192,133,
%U A073646 2225,41,237,43,1122,335,223,47,22223,77,255,173,1322,53,2333,115,2227
%N A073646 Least number formed by concatenating the prime factors of n in base 10.
%C A073646 a(n)<=A037276(n) for all n and a(n)=A037276(n) for n<22, a(22) = a(2*11) = 112 <> A037276(22) = 211.
%H A073646 Reinhard Zumkeller, <a href="/A073646/b073646.txt">Table of n, a(n) for n = 1..10000</a>
%F A073646 Sort {A027746(n,k): k=1..A001222(n)} lexicographically and concatenate. - _Reinhard Zumkeller_, Jul 13 2013
%e A073646 a(6) = a(2*3) = 23 < 32; a(66) = a(2*3*11) = 1123 < 1132 < 2113 < 2311 < 3112 < 3211.
%t A073646 con[n_, k_] := Nest[Join[{#}, {n}] &, n, k - 1]; Table[Min[FromDigits /@ Flatten /@ IntegerDigits[Permutations[Flatten[con @@@ FactorInteger[n]]]]], {n, 56}] (* _Jayanta Basu_, Jul 04 2013 *)
%o A073646 (Haskell)
%o A073646 import Data.List (sort)
%o A073646 a073646 :: Integer -> Integer
%o A073646 a073646 = read . concat . sort . map show . a027746_row
%o A073646 -- _Reinhard Zumkeller_, Jul 13 2013
%Y A073646 Different from A037276. Cf. A084797.
%K A073646 nonn,base,look
%O A073646 1,2
%A A073646 _Reinhard Zumkeller_, Aug 29 2002