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 A304686 #19 Oct 28 2021 01:29:53 %S A304686 1,2,3,4,5,7,8,9,11,12,13,16,17,19,20,23,24,25,27,28,29,31,32,37,40, %T A304686 41,43,44,45,47,48,49,52,53,56,59,61,63,64,67,68,71,72,73,76,79,80,81, %U A304686 83,88,89,92,96,97,99,101,103,104,107,109,112,113,116,117,121 %N A304686 Numbers with strictly decreasing prime multiplicities. %H A304686 Charles R Greathouse IV, <a href="/A304686/b304686.txt">Table of n, a(n) for n = 1..10000</a> %F A304686 a(n) ~ n log n. - _Charles R Greathouse IV_, Oct 28 2021 %e A304686 10 = 2*5 has prime multiplicities (1,1) so is not in the sequence. %e A304686 20 = 2*2*5 has prime multiplicities (2,1) so is in the sequence %e A304686 90 = 2*3*3*5 has prime multiplicities (1,2,1) so is not in the sequence. %t A304686 Select[Range[200],Greater@@FactorInteger[#][[All,2]]&] %o A304686 (PARI) isok(n) = my(vm = factor(n)[,2]); vm == vecsort(vm,,4) && (#vm == #Set(vm)); \\ _Michel Marcus_, May 17 2018 %o A304686 (PARI) list(lim)=my(v=List()); forfactored(n=1,lim\1, if(n[2][,2]==vecsort(n[2][,2],,8), listput(v,n[1]))); Vec(v) \\ _Charles R Greathouse IV_, Oct 28 2021 %Y A304686 Cf. A001221, A001222, A001597, A005117, A055932, A071365, A112769, A130091, A133808, A133811, A181819, A242031, A304678, A304679, A283050. %K A304686 nonn %O A304686 1,2 %A A304686 _Gus Wiseman_, May 16 2018