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 A204938 #24 Aug 03 2014 14:01:37
%S A204938 3,5,7,3,11,17,29,41,47,53,59,71,83,89,97,3,17,23,29,47,53,59,71,89,
%T A204938 113,137,173,179,191,227,239,257,281,317,347,353,359,383,401,431,443,
%U A204938 479,491,509,521,557,569,599,617,641,647,653,683,719,743,761,773
%N A204938 Irregular table T(n,k) of primes such that all terms in row n have a prime companion that sums to 10^n.
%C A204938 Row 1 has 3 terms. Row 2 has 12 terms. Row 3 has 56 terms. All rows after the first have an even number of terms.
%H A204938 T. D. Noe, <a href="/A204938/b204938.txt">Rows n = 1..5, flattened</a>
%e A204938 3+7=10, 41+59=100, 317+683=1000.
%t A204938 Flatten[Table[ps = Prime[Range[PrimePi[10^n]]]; Select[ps, MemberQ[ps, 10^n - #] &], {n, 3}]] (* _T. D. Noe_, Jan 27 2012 *)
%Y A204938 Cf. A107318 (number of terms in row n).
%Y A204938 Cf. A126691, A126692, A126693 (primes that sum to 100, 1000, and 10000).
%K A204938 nonn,tabf
%O A204938 1,1
%A A204938 _Livio Rosai_, Jan 27 2012