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 A366206 #11 Oct 06 2023 10:42:00
%S A366206 57,103,123,211,213,273,347,943,1073,1951,2185,2365,2375,2379,2501,
%T A366206 2751,2761,2855,3095,3651,3731,3791,3799,4503,4529,4843,5199,5851,
%U A366206 5927,5959,6163,7151,7305,7611,8101,8761,9045,9061,9429,9497,9741,9909,10071,10105,10401
%N A366206 Numbers k such that the sum of the first k primes is the average of a twin prime pair.
%H A366206 Paolo Xausa, <a href="/A366206/b366206.txt">Table of n, a(n) for n = 1..5000</a>
%t A366206 With[{upto=10^4},Flatten[Position[Accumulate[Prime[Range[upto]]],_?(PrimeQ[#-1]&&PrimeQ[#+1]&)]]]
%o A366206 (PARI) isok(k) = my(s=vecsum(primes(k))); isprime(s-1) && isprime(s+1); \\ _Michel Marcus_, Oct 04 2023
%Y A366206 Cf. A007504, A014574, A366205 (corresponding sums).
%K A366206 nonn
%O A366206 1,1
%A A366206 _Paolo Xausa_, Oct 04 2023