ClearAll[GenerateSmoothNumbers]
GenerateSmoothNumbers[max_?Positive] := GenerateSmoothNumbers[max, 7]
GenerateSmoothNumbers[max_?Positive, maxprime_?Positive] :=
 Module[{primes, len, vars, body, endspecs, its, data},
  primes = Prime[Range[PrimePi[maxprime]]];
  len = Length[primes];
  If[max < Min[primes],
   {}
   ,
   vars = Table[Unique[], len];
   body = Times @@ (primes^vars);
   endspecs = Prepend[Most[primes^vars], 1];
   endspecs = FoldList[Times, endspecs];
   its = Transpose[{vars, ConstantArray[0, len], MapThread[N@Log[#1, max/#2] &, {primes, endspecs}]}];
   With[{b = body, is = its},
    data = Table[b, Evaluate[Sequence @@ is]];
    ];
   data = Sort[Flatten[data]];
   data
   ]
  ]
Take[GenerateSmoothNumbers[10^8, 2], 25]
Take[GenerateSmoothNumbers[200, 3], 25]
Take[GenerateSmoothNumbers[200, 5], 25]
Take[GenerateSmoothNumbers[200, 7], 25]
Take[GenerateSmoothNumbers[200, 11], 25]
Take[GenerateSmoothNumbers[200, 13], 25]
Take[GenerateSmoothNumbers[200, 17], 25]
Take[GenerateSmoothNumbers[200, 19], 25]
Take[GenerateSmoothNumbers[200, 23], 25]
Take[GenerateSmoothNumbers[200, 29], 25]
Take[GenerateSmoothNumbers[10^40, 3], {3000, 3002}]
Take[GenerateSmoothNumbers[10^15, 5], {3000, 3002}]
Take[GenerateSmoothNumbers[10^10, 7], {3000, 3002}]
Take[GenerateSmoothNumbers[10^7, 11], {3000, 3002}]
Take[GenerateSmoothNumbers[10^7, 13], {3000, 3002}]
Take[GenerateSmoothNumbers[10^6, 17], {3000, 3002}]
Take[GenerateSmoothNumbers[10^5, 19], {3000, 3002}]
Take[GenerateSmoothNumbers[10^5, 23], {3000, 3002}]
Take[GenerateSmoothNumbers[10^5, 29], {3000, 3002}]

s = Select[Range[10^5], FactorInteger /* Last /* First /* LessEqualThan[503]];
s[[30000 ;; 30019]]
s = Select[Range[10^5], FactorInteger /* Last /* First /* LessEqualThan[509]];
s[[30000 ;; 30019]]
s = Select[Range[10^5], FactorInteger /* Last /* First /* LessEqualThan[521]];
s[[30000 ;; 30019]]