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 A136414 #18 Mar 26 2014 02:11:38 %S A136414 12,23,34,45,56,67,78,89,91,10,1,11,11,12,21,13,31,14,41,15,51,16,61, %T A136414 17,71,18,81,19,92,20,2,21,12,22,22,23,32,24,42,25,52,26,62,27,72,28, %U A136414 82,29,93,30,3,31,13,32,23,33,33,34,43,35,53,36,63,37,73,38,83,39,94,40,4,41,14 %N A136414 Put the natural numbers together without spaces and read them two at a time advancing one space each time. %C A136414 a(n) = A162711(n,2) for n>1. - _Reinhard Zumkeller_, Jul 11 2009 %H A136414 Reinhard Zumkeller, <a href="/A136414/b136414.txt">Table of n, a(n) for n = 1..10000</a> %F A136414 a(n) = 10*A007376(n) + A007376(n+1). - _Reinhard Zumkeller_, Jul 11 2009 %e A136414 34 is the third entry because the natural numbers written together look like 1234567891011 and reading them off two at a time produces 12, 23, 34, ... %o A136414 (Haskell) %o A136414 a136414 n = a136414_list !! (n-1) %o A136414 a136414_list = zipWith (+) (tail a007376_list) $ map (10 *) a007376_list %o A136414 -- _Reinhard Zumkeller_, Jul 28 2011 %Y A136414 Cf. A001704, A193431, A193492, A193493. %K A136414 easy,nonn,base,look %O A136414 1,1 %A A136414 _Ben Paul Thurston_, Mar 31 2008 %E A136414 More terms from _Reinhard Zumkeller_, Jul 11 2009