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 A259548 #25 Sep 08 2022 08:46:13
%S A259548 1,5,11,17,23,25,29,41,47,53,55,59,71,83,85,89,101,107,113,115,121,
%T A259548 125,131,137,145,149,167,173,179,187,191,197,205,227,233,235,239,251,
%U A259548 253,257,263,265,269,275,281,289,293,295,311,317,319,347,353,355,359,383
%N A259548 Numbers divisible only by primes of the form 6*m-1.
%H A259548 Charles R Greathouse IV, <a href="/A259548/b259548.txt">Table of n, a(n) for n = 1..10000</a>
%e A259548 275 is in sequence because 275 = 5*5*11, where 5 = 6-1 and 11 = 6*2-1.
%t A259548 okQ[n_] := n==1 || And @@ (Mod[#, 6]==5& /@ FactorInteger[n][[All, 1]]); Select[Range[400], okQ] (* _Jean-François Alcover_, Jul 02 2015 *)
%o A259548 (Magma) [n: n in [1..400] | forall{d: d in PrimeDivisors(n) | d mod 6 eq 5}];
%o A259548 (PARI) list(lim)=my(v=List([1]),mn,mx,t); forprime(p=5,lim\=1, if(p%6==5, listput(v,p))); if(lim<25, return(Vec(v))); forprime(p=5,sqrtint(lim), if(p%6<5, next); mx=1; while(v[mx+1]*p<=lim, for(i=mn=mx+1,mx=#v, t=p*v[i]; if(t>lim, break); listput(v,t)))); Set(v) \\ _Charles R Greathouse IV_, Jan 11 2018
%Y A259548 Subsequence of A007310.
%Y A259548 Cf. A004611 (numbers divisible only by primes of the form 6*m+1), A007528.
%K A259548 nonn
%O A259548 1,2
%A A259548 _Bruno Berselli_, Jun 30 2015