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 A325255 #16 Nov 05 2023 21:07:05 %S A325255 2,4,12,36,72,192,1152,2592,2916,1492992,1990656,5308416,28311552, %T A325255 6879707136,1761205026816,5566277615616,79164837199872, %U A325255 3799912185593856,115422332637413376,1332669751402954752,4803028329503971872 %N A325255 3-smooth numbers k such that k+1 and (k+2)/2 are prime. %C A325255 Numbers k of the form 2^a*3^b such that k+1 and (k+2)/2 are prime. %C A325255 All terms except 2 and 4 are in A325204. %C A325255 All terms except 4 end in 2 or 6. %H A325255 Ray Chandler, <a href="/A325255/b325255.txt">Table of n, a(n) for n = 1..41</a> (terms < 10^1000; first 39 terms from Robert Israel) %e A325255 a(3)=12 is a term because 12=2^2*3 and 13 and 14/2 are prime. %p A325255 N:= 10^100: # to get terms <= N %p A325255 sort(select(t -> isprime(t+1) and isprime((t+2)/2), [seq(seq(2^i*3^j, i = 1 .. ilog2(N/3^j)), j=0..floor(log[3](N)))])); %Y A325255 Cf. A003586, A325204, A327240. %K A325255 nonn %O A325255 1,1 %A A325255 _Robert Israel_, Sep 05 2019