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 A182030 #10 Nov 27 2015 12:50:07 %S A182030 1,1,3,5,27,1,3,19,15,5,33,55,123,15,115,39,127,1,23,149,27,11,393,81, %T A182030 255,125,27,129,15,115,227,195,125,89,247,71,143,1031,55,89,85,365,3, %U A182030 49,283,135,497,59,647,309,375,399,667,111,173,355,195,219,43,49 %N A182030 Least odd number k such that 3*k*2^n-1 and 3*k*2^n+1 are twin primes. %C A182030 54% of a(n) for n=1 to 1755 are < 0.1*n^2. %H A182030 Pierre CAMI, <a href="/A182030/b182030.txt">Table of n, a(n) for n = 1..1755</a> %t A182030 lon[n_]:=Module[{k=1,n2=3*2^n},While[!PrimeQ[k*n2-1]||!PrimeQ[k*n2+1], k= k+2];k]; Array[lon,60] (* _Harvey P. Dale_, Nov 27 2015 *) %Y A182030 Cf. A210651. %K A182030 nonn %O A182030 1,3 %A A182030 _Pierre CAMI_, Apr 07 2012