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 A136240 #14 Feb 11 2022 14:41:47
%S A136240 1,2,6,12,66,78,138,150,162,192,336,348,378,456,540,612,642,726,768,
%T A136240 918,990,1020,1092,1116,1200,1230,1380,1422,1548,1566,1596,1620,1692,
%U A136240 1746,1788,1800,1932,1986,2010,2016,2112,2136,2142,2238,2280,2556,2646
%N A136240 Numbers n among A006093 such that n^2 + n + 1 is prime.
%C A136240 See A074268 for the primes associated with a(n).
%H A136240 Harvey P. Dale, <a href="/A136240/b136240.txt">Table of n, a(n) for n = 1..1000</a>
%F A136240 a(n) = A065508(n) - 1.
%t A136240 Select[Prime[Range[400]]-1,PrimeQ[#^2+#+1]&] (* _Harvey P. Dale_, Feb 11 2022 *)
%o A136240 (PARI) isA136240(n) = {isprime(n+1) && isprime(n^2+n+1)} \\ _Michel Marcus_, Jul 28 2013
%Y A136240 Cf. A136241.
%K A136240 nonn
%O A136240 1,2
%A A136240 _Lekraj Beedassy_, Dec 23 2007