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 A069629 #3 Dec 05 2013 19:55:16 %S A069629 2,23,223,2237,32237,3223709,63223709,6322370909,66322370909, %T A069629 6632237090903,36632237090903,3663223709090329,73663223709090329, %U A069629 736632237090903299,5736632237090903299,573663223709090329963 %N A069629 a(1) = 2; a(2n) = smallest prime starting (most significant digits) with a(2n-1). a(2n+1) = smallest prime ending (least significant digits)in a(2n). %Y A069629 Cf. A069614 to A069621, A069628 to A069636. %K A069629 nonn,base %O A069629 1,1 %A A069629 _Amarnath Murthy_, Mar 27 2002 %E A069629 Edited and extended by _Robert G. Wilson v_, Apr 03 2002