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 A065309 #19 Dec 18 2024 22:39:01
%S A065309 0,1,3,4,8,8,12,12,12,16,18,20,24,24,24,24,30,30,36,34,32,36,40,42,44,
%T A065309 42,42,40,42,42,56,58,58,56,60,54,60,62,64,66,72,72,82,80,70,68,80,86,
%U A065309 88,80,82,82,84,88,90,90,90,90,96,90,92,100,110,112,102,94,108,110,118
%N A065309 a(n) = prime(n) - prime(n - pi(n)).
%H A065309 Harry J. Smith, <a href="/A065309/b065309.txt">Table of n, a(n) for n = 1..1000</a>
%F A065309 a(n) = A000040(n) - A000040(n - A000720(n)).
%e A065309 n=100, prime(100)=541, prime(100 - Pi(100)) = p(75), p(100) - p(75) = 541 - 379 = 162 = a(100).
%t A065309 Table[Prime[n]-Prime[n-PrimePi[n]],{n,70}] (* _Harvey P. Dale_, Apr 23 2016 *)
%o A065309 (PARI) a(n) = { prime(n) - prime(n - primepi(n)) } \\ _Harry J. Smith_, Oct 16 2009
%Y A065309 Cf. A000040, A000720, A065308-A065310.
%K A065309 nonn
%O A065309 1,3
%A A065309 _Labos Elemer_, Oct 29 2001