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 A137611 #7 Mar 31 2012 10:26:06 %S A137611 3,47,491,4919,49877,499943,4999913,49999757,499999931,4999999937, %T A137611 49999999811,499999999769,4999999998431,49999999999619, %U A137611 499999999999769,4999999999998557,49999999999998887,499999999999999679 %N A137611 Lesser of a pair of distinct closest n-digit primes that add up to 10^n. %H A137611 Hans Havermann, <a href="/A137611/b137611.txt">Table of n, a(n) for n = 1..50</a> %Y A137611 Apart from initial term, same as A124450. %Y A137611 Cf. A137612, A124450. %K A137611 nonn,base %O A137611 1,1 %A A137611 _Lekraj Beedassy_, Jan 29 2008 %E A137611 Edited by _N. J. A. Sloane_ May 15 2008 at the suggestion of R. J. Mathar. %E A137611 A-number in cross-reference corrected by _R. J. Mathar_, Jul 17 2009