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 A019491 #18 Jul 07 2018 19:16:47
%S A019491 10,20,27,28,29,34,38,44,45,46,51,52,53,54,60,61,62,69,70,74,77,78,79,
%T A019491 81,82,87,88,92,93,94,95,101,102,103,104,105,106,110,111,112,113,114,
%U A019491 115,116,117,118,120,122,124,125,126,127,130,138,139,140
%N A019491 Numbers n for which number of distinct prime divisors of binomial(n,k) has local minimum at k = n/2.
%H A019491 G. C. Greubel, <a href="/A019491/b019491.txt">Table of n, a(n) for n = 1..1000</a>
%e A019491 If n=28 then {r(C(28,k))}={0,2,3,4,4,5,6,6,6,7,8,7,7,7,6,7,7,7,8,7,6,6,6,5,4,4,3,2,0}. Thus r(C(28,14))=6 is local minimum, while r(C(28,10))=8 is maximum.
%t A019491 Select[Range[140], MatchQ[PrimeNu[Binomial[#, Range[Floor[#/2], #]]], {(x_) .., y_, ___} /; x < y]&] (* _Jean-François Alcover_, Dec 10 2016 *)
%Y A019491 Cf. A048484, A048486, A001221, A020731.
%K A019491 nonn
%O A019491 1,1
%A A019491 _Labos Elemer_
%E A019491 Data corrected by _Jean-François Alcover_, Dec 10 2016