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 A290838 #20 Dec 14 2017 20:06:13
%S A290838 2,2,3,5,5,7,7,13,11,11,11,13,13,19,17,17,17,19,19,37,23,23,23,29,29,
%T A290838 31,29,29,29,31,31,37,37,41,37,37,37,43,41,41,41,43,43,61,47,47,47,53,
%U A290838 53,67,53,53,53,59,59,61,59,59,59,61,61,67,67,71,67,67,67,73
%N A290838 a(n) = smallest prime p such that 2p - 2n + 1 is prime.
%C A290838 a(n) > n. - _Iain Fox_, Nov 13 2017
%H A290838 Iain Fox, <a href="/A290838/b290838.txt">Table of n, a(n) for n = 0..20000</a>
%F A290838 a(-n) = A290839(n+1) - _Iain Fox_, Dec 14 2017
%t A290838 Table[j=0; found=False; While[!found,j++; found=PrimeQ[2Prime[j]-2n+1] && 2Prime[j]-2n+1>0]; Prime[j],{n,67}]
%t A290838 (* Second program: *)
%t A290838 Table[SelectFirst[Prime@ Range[n^2], And[# > 0, PrimeQ@ #] &[2 # - 2 n + 1] &], {n, 67}] (* _Michael De Vlieger_, Aug 14 2017 *)
%o A290838 (PARI) a(n) = {my(p=2); while(!isprime(2*p-2*n+1), p = nextprime(p+1)); p; } \\ _Michel Marcus_, Aug 12 2017
%o A290838 (PARI) a(n) = forprime(p=n+1, , if(isprime(2*p - 2*n + 1), return(p))) \\ _Iain Fox_, Nov 13 2017
%Y A290838 Cf. A005382, A063908, A063909, A063910, A063911, A063912, A063913, A020483, A290839.
%K A290838 nonn,easy
%O A290838 0,1
%A A290838 _XU Pingya_, Aug 11 2017
%E A290838 a(0) prepended by _Iain Fox_, Dec 14 2017