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 A283427 #21 Dec 01 2019 23:17:52
%S A283427 0,1,7,26,34,55,65,91,137,152,208,251,270,315,394,471,502,591,656,685,
%T A283427 790,864,977,1139,1227,1268,1354,1395,1494,1847,1945,2109,2157,2455,
%U A283427 2512,2693,2878,3005,3202,3396,3471,3826,3902,4045,4119,4581,5059,5226,5307
%N A283427 a(n) is the number of consecutive smallest prime totatives of primorial A002110(n).
%C A283427 Let p_n# = A002110(n) be the n-th primorial, and let t be a totative of p_n#, i.e., gcd(t, p_n#) = 1. Let q be the smallest prime totative of p_n#. We know q must be p_(n+1) by the definition of "primorial" as the product of the smallest n primes. This is the starting point of the range of primes we are considering. The ending point is the smallest composite totative, which is a square semiprime. This semiprime in fact must be q^2, since q is the smallest prime totative of p_n#. Stated in terms of prime n, the range we are considering are primes p_(n+1) <= t <= prevprime((p_(n+1))^2). For the smallest primorials, q^2 > p_n# with n <= 3. Thus a(n) < A054272(n) for n <= 3.
%H A283427 Michael De Vlieger, <a href="/A283427/b283427.txt">Table of n, a(n) for n = 1..10000</a>
%F A283427 a(n) = pi(min(prime(n+1)^2, Product_{k=1..n} ( prime(k) ) )) - n.
%e A283427 a(2) = pi(min(prime(3)^2, p_2#)) - 2 = pi(min(25,6)) - 2 = 3 - 2 = 1.
%e A283427 a(4) = pi(min(prime(5)^2, p_4#)) - 4 = pi(min(121,210)) - 4 = 30 - 4 = 26.
%t A283427 Table[PrimePi[Min[Prime[n + 1]^2, Product[Prime@ i, {i, n}]]] - n, {n, 49}] (* _Michael De Vlieger_, May 16 2017 *)
%Y A283427 Cf. A000849, A054272, A283425.
%K A283427 nonn,easy
%O A283427 1,3
%A A283427 _Jamie Morken_ and _Michael De Vlieger_, May 15 2017