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 A073729 #15 Jan 27 2014 12:30:07
%S A073729 11,22,33,44,55,66,77,88,99,10,11,12,13,14,15,16,17,18,19,20,21,22,23,
%T A073729 24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,
%U A073729 47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69
%N A073729 Concatenation of initial and final digits of n in decimal representation.
%C A073729 10 <= a(n) <= 99; a(a(n))=a(n).
%H A073729 Reinhard Zumkeller, <a href="/A073729/b073729.txt">Table of n, a(n) for n = 1..10000</a>
%F A073729 a(n) = A000030(n)*10 + A010879(n).
%e A073729 a(12321)=11; a(3210123)=33; a(59387)=57; a(8923)=83.
%t A073729 Table[FromDigits[{First[x = IntegerDigits[n]], Last[x]}], {n, 69}] (* _Jayanta Basu_, Jul 08 2013 *)
%o A073729 (PARI) a(n)=10*digits(n)[1]+n%10 \\ _Charles R Greathouse IV_, Dec 28 2012
%o A073729 (Haskell)
%o A073729 a073729 n = 10 * a000030 n + a010879 n -- _Reinhard Zumkeller_, Dec 31 2012
%Y A073729 Cf. A073731, A073730.
%K A073729 nonn,base,easy,look
%O A073729 1,1
%A A073729 _Reinhard Zumkeller_, Aug 05 2002