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 A378020 #22 Nov 19 2024 02:24:40
%S A378020 0,0,1,2,1,3,4,3,5,6,5,7,6,5,8,9,8,7,10,9,11,12,11,13,12,11,14,13,12,
%T A378020 15,16,15,14,17,16,18,19,18,17,20,19,21,20,19,22,21,20,14,23,22,24,25,
%U A378020 24,26,27,26,28,27,26,23,25,24,21,29,28,30,29,28,31,32,31,30,28,29,33,34
%N A378020 a(n) = pi(A020482(n)) - pi(A020481(n)).
%F A378020 a(n) = A377972(n) - A377758(n).
%t A378020 Table[Module[{p = 2, q},
%t A378020 While[True, q = 2 n - p; If[PrimeQ[p] && PrimeQ[q], Break[]];
%t A378020 p = NextPrime[p]]; PrimePi[q] - PrimePi[p]], {n, 2, 100}]
%Y A378020 Cf. A000720, A020481, A020482, A377758, A377972.
%K A378020 nonn
%O A378020 1,4
%A A378020 _Michel Eduardo Beleza Yamagishi_, Nov 14 2024