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 A058517 #17 Mar 07 2022 13:34:26
%S A058517 2,36,66,78,96,120,126,144,156,162,186,204,210,216,222,276,288,300,
%T A058517 306,324,328,330,336,342,366,372,378,396,408,414,426,438,456,474,486,
%U A058517 498,516,528,534,540,546,552,562,576,582,606,612,624,630,636,666,672,690
%N A058517 Positive even numbers not of the form prime + 3^x.
%t A058517 Do[ i = 0; l = Ceiling[ N[ Log[ 3, n ] ] ]; While[ ! PrimeQ[ n - 3^i ] && i < l, i++ ]; If[ i == l, Print[ n ] ], {n, 2, 1000, 2} ]
%o A058517 (PARI) isok(n) = {if (n % 2, 0, lim = log(n)/log(3); for (k=0, lim, if (isprime(n - 3^k), return (0)););1;);} \\ _Michel Marcus_, Feb 25 2017
%Y A058517 Cf. A006285, A156695, A350628-A350630, A350957, A350958, A282430 (subsequence).
%K A058517 nonn
%O A058517 1,1
%A A058517 _Robert G. Wilson v_, Dec 21 2000