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 A067514 #41 Nov 15 2022 11:11:44
%S A067514 0,1,1,1,2,2,3,1,2,3,4,2,3,3,4,3,4,2,3,3,4,5,6,2,3,4,4,4,5,4,5,3,4,5,
%T A067514 6,4,5,5,6,4,5,4,5,5,5,6,7,3,4,4,5,6,7,5,6,5,6,7,8,4,5,5,5,4,5,6,7,7,
%U A067514 8,7,8,4,5,5,5,5,6,7,8,6,6,7,8,4,5,6,7,7,8,5,6,7,8,9,10,6,7,5,6,5,6,6
%N A067514 Number of distinct primes of the form floor(n/k) for 1 <= k <= n.
%H A067514 G. C. Greubel, <a href="/A067514/b067514.txt">Table of n, a(n) for n = 1..1000</a>
%H A067514 Randell Heyman, <a href="https://arxiv.org/abs/1905.00533">Cardinality of a floor function</a>, arXiv:1905.00533 [math.NT], 2019.
%H A067514 Randell Heyman, <a href="https://arxiv.org/abs/2111.00408">Primes in floor function sets</a>, arXiv:2111.00408 [math.NT], 2021
%H A067514 Randell Heyman, <a href="/A067514/a067514.pdf">Primes in floor function sets</a>, INTEGERS, vol. 22, 2022, A59.
%F A067514 a(n) = A001221(A010786(n)). - _Enrique Pérez Herrero_, Feb 26 2012
%F A067514 a(n) = 4*n^(1/2)/log(n) + O(n^(1/2)/(log(n))^2). - _Randell Heyman_, Oct 06 2022
%e A067514 a(10)=3 as floor(10/k) for k = 1 to 10 is 10,5,3,2,2,1,1,1,1,1, respectively; the 3 primes are 5,3,2.
%t A067514 a[n_] := Length[Union[Select[Table[Floor[n/i], {i, 1, n}], PrimeQ]]]
%t A067514 Table[PrimeNu[Product[Floor[n/k], {k, 1, n}]], {n, 1, 100}] (* _G. C. Greubel_, May 08 2017 *)
%o A067514 (PARI) a(n) = #select(x->isprime(x), Set(vector(n, k, n\k))); \\ _Michel Marcus_, May 04 2019
%o A067514 (PARI) a(n)=my(s=sqrtint(n+1)); sum(k=1,s,isprime(n\k))+primepi(n\s-1) \\ _Charles R Greathouse IV_, Nov 05 2021
%Y A067514 Cf. A068050.
%Y A067514 Cf. A055086 (number of distinct integers with same form). - _Michel Marcus_, May 04 2019
%K A067514 easy,nonn
%O A067514 1,5
%A A067514 _Amarnath Murthy_, Feb 12 2002
%E A067514 Edited by _Dean Hickerson_, Feb 12 2002