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 A128654 #7 Jul 22 2020 11:35:43
%S A128654 263,821,953,1049,1597,2143,2273,2677,2683,2699,2749,3251,3389,3709,
%T A128654 3739,3761,3929,4013,4243,4409,4519,4603,4621,4639,4657,4943,5009,
%U A128654 5387,5449,5483,5783,6173,6311,6373,6703,6737,6869,6983,7517,7603,7717,7993
%N A128654 Primes occurring in A084704 exactly thrice.
%e A128654 263 occurs as the 42nd, 51st and 53rd terms: (prime(#)+263)/2/(AT){43,52,54}= {227,251,257} primes.
%Y A128654 Cf. A084704, A128653, A128655.
%K A128654 nonn
%O A128654 1,1
%A A128654 _Zak Seidov_, Mar 18 2007