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 A309277 #8 Apr 20 2020 18:38:10
%S A309277 5,7,8,9,12,15,16,19,20,21,24,25,28,32,33,36,39,40,43,44,45,48,52,55,
%T A309277 56,60,61,63,64,68,69,72,73,75,76,80,81,84,88,91,92,96,99,100,104,105,
%U A309277 108,109,111,112,115,116,120,124,128,132,133,136,140,141,144
%N A309277 Sums of two primes whose difference is squarefree.
%e A309277 5 is in the sequence since 5 = 2 + 3 (both prime) and 3 - 2 = 1 is squarefree.
%e A309277 8 is in the sequence since 8 = 5 + 3 (both prime) and 5 - 3 = 2 is squarefree.
%t A309277 Flatten[Table[If[Sum[(PrimePi[i] - PrimePi[i - 1]) (PrimePi[n - i] - PrimePi[n - i - 1]) MoebiusMu[n - 2 i]^2, {i, Floor[(n - 1)/2]}] > 0, n, {}], {n, 150}]]
%Y A309277 Cf. A309152.
%K A309277 nonn
%O A309277 1,1
%A A309277 _Wesley Ivan Hurt_, Jul 20 2019