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 A034782 #20 May 13 2018 19:53:22
%S A034782 24,32,34,64,76,80,92,94,104,110,122,124,132,144,152,154,182,202,206,
%T A034782 214,220,236,242,244,246,252,274,286,294,302,322,332,340,344,356,362,
%U A034782 364,374,376,390,412,416,434,474,482,484,494,496
%N A034782 Numbers n such that A034693(n) = 3: 3n + 1 is prime, but neither n + 1 nor 2n + 1.
%H A034782 Michael De Vlieger, <a href="/A034782/b034782.txt">Table of n, a(n) for n = 1..10000</a>
%t A034782 Position[#, 3] &@ Table[k = 1; While[! PrimeQ[k n + 1], k++]; k, {n, 500}] // Flatten (* _Michael De Vlieger_, Mar 02 2017 *)
%o A034782 (PARI) is(n)=!isprime(n+1)&&!isprime(2*n+1)&&isprime(3*n+1) \\ _M. F. Hasler_, May 13 2018
%Y A034782 Cf. A034693, A034694.
%K A034782 nonn
%O A034782 1,1
%A A034782 _Labos Elemer_
%E A034782 Corrected by _R. J. Mathar_, Jul 26 2015
%E A034782 Name edited by _M. F. Hasler_, May 13 2018