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 A157942 #10 Jul 25 2024 14:08:56 %S A157942 4,6,8,9,12,15,18,21,24,25,30,35,40,45,49,56,63,70,77,84,91,98,105, %T A157942 112,119,121,132,143,154,165,169,182,195,208,221,234,247,260,273,286, %U A157942 289,306,323,340,357,361,380,399,418,437,456,475,494,513,529,552,575,598 %N A157942 Numbers n divisible by the largest prime <= sqrt(n), A007917(A000196(n)). %C A157942 Includes squares of primes (A001248; exactly the cases where we have "=" in the definition) and products of pairs of consecutive primes (A006094) as subsequences. %t A157942 Select[Range[4,599],IntegerQ[#/Prime[PrimePi[Sqrt[#]]]]&] (* _Jayanta Basu_, May 03 2013 *) %o A157942 (PARI) for( n=4,999, n % precprime(sqrtint(n)) || print1(n",")) %K A157942 nonn %O A157942 1,1 %A A157942 _M. F. Hasler_, Mar 09 2009