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 A129820 #9 Apr 24 2020 18:54:29
%S A129820 25,27,33,35,49,51,55,57,63,65,75,77,85,87,91,93,93,95,115,117,117,
%T A129820 119,119,121,121,123,123,125,133,135,141,143,143,145,145,147,153,155,
%U A129820 159,161,169,171,175,177,183,185,185,187,187,189
%N A129820 List of pairs of consecutive nonprime odd numbers {m-1,m+1}.
%t A129820 Flatten[Table[If[OddQ[n - 1] && PrimeQ[n - 1] == False && PrimeQ[n + 1] == False, {{n - 1}, {n + 1}}, {}], {n, 2, 200}]]
%t A129820 Select[Partition[Range[1,201,2],2,1],NoneTrue[#,PrimeQ]&]//Flatten (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Apr 09 2019 *)
%Y A129820 Cf. A061673, A093708.
%K A129820 nonn
%O A129820 1,1
%A A129820 _Roger L. Bagula_, May 20 2007