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 A074661 #19 Oct 18 2020 03:09:56
%S A074661 4,8,9,12,18,20,24,25,27,28,32,36,40,44,45,49,50,52,54,56,60,63,68,72,
%T A074661 75,76,84,88,90,92,96,98,99,100,104,108,116,117,120,121,124,125,126,
%U A074661 128,132,135,136,140,147,148,150,152,153,156,160,164,168,169,171,172,175,180,184
%N A074661 Let n = 2^e_2 * 3^e_3 * 5^e_5 * ... be the prime factorization of n; sequence gives n such that max{e_2, e_3, ...} is prime.
%C A074661 The old entry with this sequence number was a duplicate of A056594.
%C A074661 The largest exponent of the prime factors of n is prime. - _Harvey P. Dale_, Mar 09 2012
%C A074661 The asymptotic density of this sequence is Sum_{p prime} (1/zeta(p+1) - 1/zeta(p)) = 0.3391101054... - _Amiram Eldar_, Oct 18 2020
%H A074661 Amiram Eldar, <a href="/A074661/b074661.txt">Table of n, a(n) for n = 1..10000</a>
%t A074661 Select[Range[200],PrimeQ[Max[Transpose[FactorInteger[#]][[2]]]]&] (* _Harvey P. Dale_, Mar 09 2012 *)
%o A074661 (PARI) isA074661(n) = if(n<4,0,isprime(vecmax(factor(n)[,2])))
%Y A074661 Cf. A096432, A060476.
%K A074661 nonn
%O A074661 1,1
%A A074661 _N. J. A. Sloane_, Sep 18 2008