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 A004788 #28 Apr 01 2018 21:01:32
%S A004788 0,0,1,1,2,2,3,3,3,3,4,5,5,5,5,5,6,6,7,7,7,7,8,9,8,8,8,8,9,10,10,10,
%T A004788 10,10,10,11,11,11,11,12,12,12,13,13,14,13,14,15,14,14,14,14,15,15,15,
%U A004788 16,15,15,16,17,17,17,18,17,17,17,18,18,18,19,19,20,20
%N A004788 Number of distinct prime divisors of the numbers in row n of Pascal's triangle.
%C A004788 Also the number of prime divisors of A002944(n) = lcm_{j=0..floor(n/2)} binomial(n,j).
%C A004788 The terms are increasing by intervals, then decrease once. The local maxima are obtained for 23, 44, 47, 55, 62, 79, 83, 89, 104, 119, 131, 134, 139, 143, .... - _Michel Marcus_, Mar 21 2013
%C A004788 a(A004789(n)) = n and a(m) != n for m < A004789(n). - _Reinhard Zumkeller_, Mar 16 2015
%H A004788 T. D. Noe, <a href="/A004788/b004788.txt">Table of n, a(n) for n = 0..1000</a>
%F A004788 a(n) = A001221(A001142(n)). - _Reinhard Zumkeller_, Mar 16 2015
%t A004788 Table[prd = Product[Binomial[n, k], {k, 0, n}]; If[prd == 1, 0, Length[FactorInteger[prd]]], {n, 0, 100}] (* _T. D. Noe_, Mar 21 2013 *)
%o A004788 (PARI) a(n) = {sfp = Set(); for (k=1, n-1, sfp = setunion(sfp, Set(factor(binomial(n, k))[,1]))); return (length(sfp));} \\ _Michel Marcus_, Mar 21 2013
%o A004788 (Haskell)
%o A004788 a004788 = a001221 . a001142 -- _Reinhard Zumkeller_, Mar 16 2015
%Y A004788 Cf. A004789.
%Y A004788 Cf. A001221, A001142, A256113.
%K A004788 nonn
%O A004788 0,5
%A A004788 _Clark Kimberling_