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 A193492 #13 Jul 13 2013 12:04:13 %S A193492 1234,2345,3456,4567,5678,6789,7891,8910,9101,1011,111,1112,1121,1213, %T A193492 2131,1314,3141,1415,4151,1516,5161,1617,6171,1718,7181,1819,8192, %U A193492 1920,9202,2021,212,2122,1222,2223,2232,2324,3242,2425,4252,2526,5262,2627,6272 %N A193492 Put the natural numbers together without spaces and read them four at a time advancing one space each time. %H A193492 Reinhard Zumkeller, <a href="/A193492/b193492.txt">Table of n, a(n) for n = 1..10000</a> %F A193492 a(n) = 10*(10*(10*A007376(n)+A007376(n+1))+A007376(n+2))+A007376(n+3). %t A193492 FromDigits/@Partition[Flatten[IntegerDigits/@Range[30]],4,1] (* _Harvey P. Dale_, Aug 19 2012 *) %o A193492 (Haskell) %o A193492 a193492 n = a193492_list !! (n-1) %o A193492 a193492_list = f a007376_list where %o A193492 f xs'@(x:xs) = ((foldl (\u v -> 10*u + v) 0) $ take 4 xs') : f xs %Y A193492 Cf. A136414, A193431, A193493. %K A193492 nonn,base %O A193492 1,1 %A A193492 _Reinhard Zumkeller_, Jul 28 2011