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 A321193 #18 Dec 13 2021 21:19:40
%S A321193 2,4,6,8,10,12,14,16,18,20,22,24,26,28,32,34,36,38,40,44,46,48,50,52,
%T A321193 54,56,58,62,64,68,72,74,76,80,82,86,88,92,94,96,98,100,104,106,108,
%U A321193 112,116,118,122,124,128,134,136,142,144,146,148,152,158,160,162,164,166,172,176,178,184,188,192,194,196
%N A321193 Even numbers with no more than one odd prime factor, not counting multiplicity.
%H A321193 Charles R Greathouse IV, <a href="/A321193/b321193.txt">Table of n, a(n) for n = 1..10000</a>
%F A321193 Numbers of the form 2^k*p^h where k > 0, h >= 0 p is an odd prime.
%F A321193 a(n) = 2 * A070776(n-1) for n > 1. - _Alois P. Heinz_, Nov 20 2018
%e A321193 18 = 2 * 3^2 is in the sequence because it has 1 odd prime factor (3 counts only once).
%e A321193 16 = 2^4 is in the sequence because it has no odd prime factors.
%e A321193 70 = 2 * 5 * 7 is not in the sequence because it has 2 odd prime factors.
%t A321193 n = 0; Table[n = n + 2;
%t A321193 While[Length[FactorInteger[n]] > 2, n = n + 2]; n, {k, 1, 76}]
%o A321193 (PARI) is(n) = n%2==0 && omega(n) <= 2 \\ _Felix Fröhlich_, Nov 01 2018
%o A321193 (PARI) is(n)=my(o=valuation(n,2)); o && isprimepower(n>>o) \\ _Charles R Greathouse IV_, Dec 13 2021
%o A321193 (PARI) list(lim)=my(v=List()); for(k=1,logint(lim\=1,2), listput(v,1<<k)); for(k=1,logint(lim\9,2), my(L=lim>>k); for(e=2,logint(L,3), forprime(p=3, sqrtnint(L,e), listput(v,p^e<<k)))); for(k=1,logint(lim\3,2), forprime(p=3, lim>>k, listput(v,p<<k))); Set(v) \\ _Charles R Greathouse IV_, Dec 13 2021
%Y A321193 Cf. A070776, A100367, A001221, A098902, A100368.
%K A321193 nonn,easy
%O A321193 1,1
%A A321193 _Lei Zhou_, Oct 29 2018