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 A087091 #12 Dec 27 2019 11:50:56
%S A087091 1,4,10,16,19,31,34,43,55,58,61,70,73,79,85,94,100,118,148,154,160,
%T A087091 175,196,199,211,214,223,226,229,238,253,274,313,340,424,430,469,499,
%U A087091 508,529,538,541,550,565,640,658,673,706,724,760,763,781
%N A087091 Numbers k such that p = k^2 + k + 41 and p - 2 are twin primes.
%H A087091 Amiram Eldar, <a href="/A087091/b087091.txt">Table of n, a(n) for n = 1..10000</a>
%e A087091 4 is in the sequence because 61 = 4^2 + 4 + 41 and 59 are twin primes.
%t A087091 Select[Range[10^3], And @@ PrimeQ[#^2 + # + {39, 41}] &] (* _Amiram Eldar_, Dec 27 2019 *)
%o A087091 (PARI) isok(n) = isprime(n^2+n+41) && isprime(n^2+n+39); \\ _Michel Marcus_, Oct 03 2013
%Y A087091 Cf. A007634, A087090.
%K A087091 nonn
%O A087091 1,2
%A A087091 _Zak Seidov_, Aug 08 2003