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 A066264 #16 Feb 16 2025 08:32:45
%S A066264 0,0,0,5,141,2517,49835,1012858,24211837,721500293,22627459400,
%T A066264 844130935667,34729870646917,1491483322755273,69890000837179156
%N A066264 Number of composites < primorial(p) with all prime factors > p.
%C A066264 There is a simple relationship between this sequence and the number of primes < primorial(p), as given by A000849 and sequence A005867 which gives the number of composites in primorial(p+1) having (p+1) as their lowest prime factor: a(n) = n + A005867(n) - A000849(n) - 1. - Dennis Martin (dennis.martin(AT)dptechnology.com), Apr 15 2007
%H A066264 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Primorial.html">Primorial</a>
%F A066264 a(n) = n + A005867(n) - A000849(n) - 1. - _Michael De Vlieger_, Apr 03 2019, citing Dennis Martin's comment above.
%e A066264 There are 5 composites < primorial(7) or 210 and whose prime factors are all larger than 7: 121 (11*11), 143 (11*13), 169 (13*13), 187 (11*17) and 209 (11*19).
%t A066264 Array[#1 + EulerPhi@ #2 - PrimePi@ #2 - 1 & @@ {#, Product[Prime@ i, {i, #}]} &, 12] (* _Michael De Vlieger_, Apr 03 2019 *)
%Y A066264 Cf. A000849, A002110, A005867.
%K A066264 nonn
%O A066264 1,4
%A A066264 _Patrick De Geest_, Dec 10 2001
%E A066264 More terms from Dennis Martin (dennis.martin(AT)dptechnology.com), Apr 15 2007
%E A066264 Offset corrected by Charles J. Daniels (chajadan(AT)gmail.com), Dec 06 2009
%E A066264 a(14)-a(15) from _Donovan Johnson_, May 03 2010