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 A220144 #8 Dec 30 2019 10:05:57
%S A220144 4,6,9,18,24,42,54,120,258,396,420,594,744,840,1074,1800,2130,2172,
%T A220144 2256,2304,2550,2778,3282,3792,3894,4170,4488,4578,4626,4848,5562,
%U A220144 5754,6192,6252,7260,7428,7920,9654
%N A220144 The values of k in A220143.
%t A220144 t = {{1, 4}}; Do[k = 1; While[! (PrimeQ[k*n - 1] && PrimeQ[k*n + 1]), k++]; If[k > t[[-1, 2]], AppendTo[t, {n, k}]], {n, 2, 100000}]; Transpose[t][[2]]
%Y A220144 Cf. A071558, A220143.
%K A220144 nonn,more
%O A220144 1,1
%A A220144 _T. D. Noe_, Jan 08 2013
%E A220144 More terms from _Amiram Eldar_, Dec 30 2019